THE IDENTITY OF PHOMA PITYA SACC.,PHOMA ABIETINA HART. AND THEIR RE­LATION TO PHOMOPSIS PSEUDOTSUGAE

WILSON-.By Malcolm Wilson, D.Sc., F.R.S.E., F.L.S. and

Glenn Gardner Hahn, B.Sc., M.Sc.(From the Mycological Department, University of Edinburgh.)

(With Plates XVIII-XXI.)

INTRODUCTION.DURING the last fifty years there have been numerous refer­ences in the literature, both mycological and forestry, to Phomapitya Sacco t and Phoma abietina Hartig (Fusicoccum abietinumPrill. & Delacr.) and a considerable number of diseases of conifershave been attributed to these species. Recently a new speciesclosely allied to these, Phomopsis Pseudotsugae Wilson, has beendescribed (59,60,64) as the cause of a disease of the Douglas fir(Pseudotsuga Douglasii) and other conifers in Great Britain. Onaccount of the confusion now existing in the literature as to theidentity of the fungi described during the latter half of the lastcentury, the question has arisen of the relation existing betweenthem and the newly described fungus.

HISTORY.Phoma pitya Sacco was described in 1878 by Saccardo from

specimens collected on twigs of Pinus sylvestris by P. Magnus inthe Botanic Garden at Berlin. The fungus was found on deadtwigs and there is no evidence that it was parasitic.

Rostrup in Denmark was the first to associate Phoma pityawith disease in conifers. Writing in 1885 (46) he states, " A ratherlarge plantation of Picea excelsa (Rottanne) planted in 1882,with four year old trees, had a most distressing appearancebecause of thousands of withered plants. On numerous plantswhich I examined there was always found, on the lower partof the stem, partly a little above ground and partly underground, a portion about two inches long covered with numeroussmall black fructifications, which by a critical examination

* Grateful acknowledgment is due to Miss E. M. Wakefield, of the RoyalBotanic Gardens, Kew, and to Mr J. Ramsbottom of the British Museum, forvaluable critical assistance in the manuscript preparation.

t The Greek for pine being 1riTus, Saccardo's incorrect orthography has beencorrected. Where an author is quoted directly, the orthography used by him isfollowed.

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after my return home proved to belong to Ph oma p ithy a. Thisspecies is not hithert o known as a parasite and only it s constantassociation in the same locality with all the dead and diseasedplants indicates that it bears some relation to t he devas tation.The roots of t he withered plants were well developed and showedno injury from insects and there was on t he whole no cause otherthan the fungus which appeared tobe responsible for the disease."

He gave a further account of the disease on PseudotsugaDouglasii and Abies peciinata in 1890 (47) and here states thatPhoma pitya is identical with Ph oma abietina Hartig, and liststhe disease in his Plantepatologi in 1902 on Ps eudotsuga Doug­lasii, Abies pectinata, A . balsamea, Picea excelsa, P inus sylvestris,P . montana, P. Strobus and Larix europaea. He also record edthe fungus from Bornholm in 1906 on Pseudotsuga Douglasii andP inus Stro bus.

Meanwhile a somewhat similar disease (PI. XX, figs. 7, 8) hadbeen described in Germany in 1889 on Abies pectinata byHartig (19) who was of the opinion that it was caused by a newspecies" der Tannenrindenpilz ," which he nam ed provisionallyPhoma abietina . He records the disease from the BavarianForest, the Bavarian Alps and the Black Forest , stating that"sehr grossen Schaden anrichtet" in the first named locality.The disease is describ ed in his text-book and in the Engli shtranslation of this work by Somerville and Marshall Ward (21).

Shortl y after Hartig's discovery Prillieux and Delacroix (42)

reported the same disease (PI. XX, figs. 7, 8) from Gerardmer,Vosges, France in 1890 on Abies pectinata stating at first thatit was due to the fungus Dothiorella pitya Sacc., but later (43 )giving it the combination Fusicoccum abietinum (Hart.) Prill .& Delacr. They regarded their fungus as identical with Phomaabietina Hart., upon the examination of a specimen of thisfungus sent to them by Hartig. This disease was also describedby Mer in 1890 from Gerardmer, and a further detailed accoun tof the effect of the fungus on the silver fir in France was pub­lished by him in 1893. He identified the fungus as P. abietin aHart. (F . abietinum Prill. & Delacr.) Oth er French accounts ofan outbreak of the disease on the silver fir in t he Jura in 1907were given by Henry (23 , 24,25) Prillieux and Maublanc (44),

Maublanc (34) and Mer (37). Amongst t hese authors Mer app earsto prefer the original name Phoma abietina for the fungus.Prilli eux (41 ) has also publi shed an account of Fusicoccumabietinum on A bies p ectinata in his text-book on plant diseases.

Bohm in 1896 gave an account of the attack of Phomaabietina on the Douglas fir in North Germany. His determin­ation of the fungus was verified by P . Magnus and the descrip­tion given is that of Fusicoccum abietinum as quoted from

Phoma pitya Saee. and Phoma abictina Hart . 263

Saccardo ((51), vol. x). Bohm pointed out that up to that timethis fungu s had been recorded only on Abies pectinate. Bohrri'spaper was reviewed by Forbes in 1896. The parasites P. abietina(F. abietinum) on Abies pectinata, and P . pitya on PseudotsugaDouglasii were discussed by Tubeuf in his text-book publishedin 1895 and translated into English by Smith in 1897. Tubeufdrew attention to Rostrup's description of P . pitya quoted ab oveand mentioned that it closely resembled P. abietina. In a foot­note in the English translation Smith suggested that there hasbeen some confusion between the two species. Allescher (2)

described both P. pitya and F. abieiinum in Rabcnhorst'sKryptogamen-Flora. He gave Dothiorella pitya Prill. & Delacr.nee Sacc., and Phoma abietina Hart. as synonyms for F. abieti­num. Prill. & Delacr.

Meanwhile Somerville in 1898 had identified as "almostcertainly Phoma pitya Sacc." a fungus found on a diseasedDouglas fir in Scotland by Leven (30) . The same fungus wasrecorded by Farquharson (1 3) on this host near Aberdeen.

Schwappach in 1909 recorded" Phoma pythia (P. abietina;"as the cause of a disease of Pseudotsuga Douglasii and Piceasitchensis in Eberswalde, Korth Germany, and stated thatBohm (6) had already discussed the disease from a mycologicalstandpoint. Lindau in 1908 in Sorauer's text-book referred toPhoma pitya as the cause of the" Einschniirungskrankhcit " ofthe Douglas fir, and to Fusicoccum abietinum as the cause ofa disease on the silver fir designated by the same term.

Lind in 1913 in his account of Rostrup's herbarium described"T'homopsis pithya (Sacc.) Lind," and gave as synonyms­"Phoma pithya Sacc., Phoma abietina Hartig, Fusicoccumabietinum Prill . et Del." He referred to it as a true parasiteand recorded it on Abies balsamea, A . pectinata, A. concolor,Picea excelsa, Pinus sylvestris, P. montana, P . Strobus, Pseudo­tsuga Douglasii and Juniperus oirginiana. Grove (16) stated thatthe fungus which Lind called Phomopsis pitya (Sacc.) wasidentical with Phoma abietina Hart. but not with Phoma pityaSacco (although Lind himself gives the latter as a synonym), andthat the correct name for the species should be Phomopsisabietina (Hart .) Grove. In 1921 he further stated that Ph.abietina was very probably polymorphic having a Phomopsisstate, a Fusicoccum state, a Dothiorella state, and probably aS clerophoma state. He regarded the species as "a decidedparasite, doing great harm to numerous species of Coniferae onthe Continent" and suggested that it might become equallydangerous in the Scottish forests.

Recently in 1920 a disease of the terminals of the side branchesof Douglas fir was reported by the Biologische Reichsanstalt (3)

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as occurring at Stettin, which was regarded as being caused byPhomapitya, and Hausrath (22) in 1921-2,recorded the appearanceof a disease of the branches among 25-30 year old Douglas fircaused by P. abietina in the forests at Oberweiler and Bruchsal.De Koning ( (29) Figs. 82, 83) in Holland has described a diseaseof the Douglas fir which is referred to by the name" Insnoerings­ziekte" and states that it is caused by "Phoma pytia Sacc.,"which he remarks, "is the most noteworthy species of the genusPhoma that is harmful to woody plants." He observed it inmany places in Holland. He also mentioned the disease on thesilver fir caused by P. abietina. Neger (38) gave a short descrip­tion of the "Einschniirungskrankheiten" caused by Phomaabietina on Abies pectinata and by P. pitya on PseudotsugaDouglasii and Pinus Strobus. He regarded Phoma pitya as aparasite of juvenile stock of two or three year old plants. Hefigured ((38), p. 174, Abb. 134) young plants of Pinus Strobusaffected with Phoma pitya, and a pycnidium and spores of whathe considered to be Saccardo's fungus.

Doidge (II) in 1924 in a preliminary list of the plant diseasesof South Africa included Phoma abietina on Pinus sp. from theTransvaal and from the Orange Free State, and on Cupressus sp.from the Transvaal. Stevenson in 1926 quoted Fusicoccumabietinum as occurring on Abies Veitchii (4) in Ohio, United Statesof America.

The most recently described European disease of the Douglasfir (PI. XXI, figs. II, 12, 13, 14) closely related to Phoma pityaand P. abietina and attributed to Phomopsis Pseudotsugae wasdescribed by the senior author in 1925 (59,64). This fungus islisted by Hickel (26) as synonymous with" Phoma pythia (Ph.abietina)" among the diseases of the Douglas fir in Europe.Fabricius in 1926 recorded the attack of P. pitya on the leadingshoots of the Douglas fir in Denmark but he considers that thefungus is generally saprophytic and often associated with frostdamage. He refers to the closely related fungus Ph. Pseudotsugaeand states that this has not been found in Denmark.

A perusal of the foregoing literature demonstrates not onlythe great confusion regarding the identity of the causal speciesof the various diseases, but also the apparently wide distributionof the two earlier known fungi. In the course of time the namesPhoma pitya and P. abietina have almost been regarded by someauthorities as interchangeable and have been used in certaincases indis.criminately to indicate the fungi concerned. In orderto clear up this confusion an examination of the type specimenof P. pitya has been made and authentic specimens of P. abietinaand Fusicoccum abietinum have also been examined and com­pared with specimens of Phomopsis Pseudoisugae.

Phoma pitya Sacco and Phoma abietina Hart. 265

THE IDENTITY OF PHOMA PITYA SACCo

The name Phoma pitya was first used by Saccardo in 1878 forthe fungus collected by Magnus on dead branches of Pinussylvestris in the Berlin Botanic Garden (PI. XVIII, fig. I). Someconfusion has arisen owing to the fact that Thiimen in hisMycotheca universalis, No. 1888, 1876, had used the samespecific name pitya for a fungus on larch which he described asSphaerapsis pitya Thiim.

Von Hohnel in 1909 instituted the new genus Sclerophoma andin it included Sphaeropsis pitya Thurn. This fungus which occurson Larix europaea, had been removed by Saccardo ((51), vol. x)in 1892 to Phoma, and owing to the existence of Phoma pityaSacco it was necessary in so doing to change its specific name; itbecame therefore P. pityella Sacco Diedicke (9), in 19II gave afuller description of the genus Sclerophoma, and cited S. pitya(Sacc.) v. Hahn. as a species placed in the genus by von H6hnel.This is evidently a misquotation since the species included byvon Hohnel under the name Sclerophoma pitya (Thum.) V. Hahn.was Sphaeropsis pitya Thurn. and not Phoma pitya Sacco In 1912Diedicke perpetuated this error in the Flora of the Mark Bran­denburg by quoting" Sclerophoma pitya (Sacc.) V. Hahn." assynonymous with" Phoma pitya Sacco Mich. I, S. 126; Syll. III, S.173*; Allescher, VI, S. 196." Lind (31), did not appear to recogniseSclerophoma as a genus and placed S. pitya (Thiim.) V. Hahn.under Phoma pityella Sacco He created a new combinationPhomopsis pitya in which he included not only Phoma pityaSacco but also P. abietina Hart.

Grove in 1918 in discussing the genera Phomopsis andSclerophoma gave a description of the latter but cited Diedickeas the authority for the genus. He described the species"Sclerophoma pithya Died., Pilz Brand. IX, 280 (? non V. Hahn.Fragm. Mykol., No. 402, 1909)," and gives amongst others, assynonyms "Phoma pithya Sacc." and .. ? Phomopsis pithyaLind., Dan. Fung. p. 421,1913, = Phoma abietina Hartig (1888),= Fusicoccum abietinum Prill. et Delacr." Although Groveincludes "? Phomopsis Pithya Lind" in this list of synonyms,he later (17) explicitly states it cannot be Sclerophoma pityaDied.

It should be noted that Grove cites Diedicke as the authorityfor Sclerophoma pitya although Diedicke himself in the Pill,Brandenburg cites von Hohnel as the authority. However, sinceDiedicke was the first author to publish the combinationSclerophoma pitya (Sacc.), Grove was justified by the rules ofnomenclature in attributing this combination to him.

• This is a misquotation for 73.

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Van Luyk in 1923 discussed Diedicke's incorrect citation ofvon Hohnel and raised the question of the identity of Diedicke'sfungus. He stated "Wenn der von Diedicke beschriebenePilz eine gute Sclerophoma-Art und mit Phoma pitya Saccoidentisch ist, muss er also Sclerophoma pitya (Sacc.) Died.heissen." It appears that van Luyk was not prepared to makea definite statement as he had not seen the type specimen ofPhoma pitya. He appeared to incline to the opinion that it wasa species of Phomopsis for he stated" Da Saccardo diesen Pilzfur die wahrscheinliche Nebenfruchtform von Diaporthe pityaSacco holt, ist es sehr wahrscheinlich, dass Lind mit Recht denPilz als eine Phomopsis betrachtet." Petrak in 1923 in dis­cussing the problem was evidently also of this opinion; he stated"Phoma pitya Sacc.... schon Saccardo angegeben hat dass dieseArt als Nebenfrucht zu einer Diaporthe gehoren soll. Ich glaubenun, dass diese Vermutung Saccardo's richtig und sein Pilz einePhomopsis sein wird."

In order to solve definitely this problem the examination ofthe type specimen of Phoma pitya Sacco was necessary-anecessity which had already been pointed out by van Luyk­"Eine Prilfung des Originalexemplars der Phoma pitya Saccoware daher sehr wiinschenswert." By the courtesy of ProfessorGola, the Director of the Royal Botanic Garden at Padua wehave been permitted to examine the type specimen of P. pityaSacco : upon a critical examination the species has been provision­ally assigned to Sclerophoma; it therefore becomes Sclerophomapitya. Although there is no evidence that Diedicke had ever seenthis type specimen, yet judging from his description of the funguswhich he had on Pinus sylvestris from Thuringia and our presentknowledge, he was probably correct in his identification.

The question arises whether Phoma pitya Sacco is identicalwith Thiimen's Sphaeropsis pitya. We have not been able toexamine the type specimen of the latter, but have seen a funguscollected by Rehm and distributed by Thiimen in his Myco­theca universalis, No. 1888. This specimen, which was examinedthrough the courtesy of the Keeper of Botany of the BritishMuseum (Natural History) is a Sclerophoma but clearly differsfrom P. pitya in spore size and shape. The spores of Sphaeropsiepitya as given by Thumen are 4-7 x 2-2'511- and are ellipticalor ovate, while those of P. pitya are characteristically fusoidand according to Saccardo measure 9-II x 2'5-3'511-'

A consideration of the foregoing discussion shows that thereare two species of Sclerophoma with the same specific name­Scl. pitya (Thiim.) V. Hahn. and ScI. pitya (Sacc.) Died. One ofthese must be changed and since the combination was firstused for Thiimen's fungus it must be retained for this species.

Phoma pitya Sacco and Phoma abietina IIart. 267

Consequently a new name is required for Saccardo's fungus.We therefore propose to name it Sclerophoma Magnusiana inhonour of Professor Paul Magnus who discovered it in 1878.

Sclerophoma Magnusiana Wilson & Hahn.Phoma pitya Sacc., Mich. I, 126, 1879, Sylloge, III, 73; Scl. pitya

(Sacc.) Died., non Set. pitya (Thiim.) v. Hohn.Pycnidia distributed in close set rows or sparsely aggregated

or scattered (PI. XVIII, fig. 2), primordia distinct or arising closeto adjacent primordia and fusing laterally, formed just belowthe epidermis in the uppermost layers of the bark parenchyma,soon becoming erumpent or subsuperficial as subspherical orcushion-shaped fruiting bodies which appear to sit almostsuperficially upon the bark surface (PI. XVIII, fig. 3) when theoutermost layers flake off; dull black, carbonaceous, with agranular surface; I2S-460p. wide, 187·S-350p. high, at firstcompletely closed, then breaking open irregularly without adefinite ostiole. Pseudoparenchymatous cells of the outer­pycnidial wall, sclerotioid, thick-walled, polygonal, fuliginous,gradually passing into the cells of the inner wall which are onlyfaintly tinged or hyaline, and which face into a cavity withoutintervening conidiophores (PI. XIX, fig. 4); cavity at maturitycompletely filled with spores. The spores arise directly from thecell walls, being produced by a budding process, wherein thecontents of the inner peripheral cells lining the cavity are ex­truded to form spores (PI. XIX, fig. 5); these are embedded ina colourless gelatinous matrix resulting from a histolysis of theprimordial cells of the inner pycnidial structure. Spores uni­cellular, hyaline, characteristically spindle-shaped but varyingto ovate; extremities acutely pointed, or gently rounded, be­coming obtuse, symmetrical or asymmetrical; 6 -12 X 2·5-4p.,commonly 8-10 x 3-3·5p., many with a single large vacuole(PI. XIX, fig. 6). The perfect stage is unknown. Saccardo associ­ated Diaporthe pitya Sacco with this fungus.

On dead twigs of Pinus sylvestris collected by P. Magnus inthe Botanical Garden, Berlin, Germany, 1878 (specimen pre­served in the herbarium of the Royal Botanic Garden, Padua,Italy). Also collected in Great Britain by J. W. Ellis on Pinussyluestris at Higher Bebington, Cheshire, England, April yth,1912, and by Dr J. W. Munro, on young Scots pine, April, 1922(specimens examined through the courtesy of the Director,Royal Botanic Gardens, Kew, England).

Grove (16) reports-" Sclerophoma pithya Died. (? non v.Hohn.) on small dead branches of Pinus sylvestris, King's Lynn(Plowright); Cheshire (Ellis). On the same, Edgbaston BotanicGardens, Birmingham. March-April. Plowright's specimens

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were sent to me so long ago as 1881, mixed with CenangiumAbietis Rehm, but remained unnoticed till this year (1918)....Sclerophoma, so far as at present known, appears to be onlysaprophytic." The specimen collected by Ellis in Cheshire towhich Grove refers, is probably identical with that in the KewHerbarium which we have identified as Sclerophoma Magnu­siana. This fungus possesses spindle-shaped spores 8-12 x 3-41-'-'The specimen was not recorded as parasitic. We have not seenthe other specimens reported by Grove.

Phoma cembrae Karst. and Sporonema strobilinum var. ramu­lorum Vesterg. are given as synonyms for Sclerophoma pityaDied. by Grove. We have not seen the type specimens of thesespecies and are unable to state whether they are identical withScl. M agnusiana.

Rostrup (48,49) identified a number of specimens from Den­mark as Phoma pitya. These, which occur on a number of conifers,are preserved in the herbarium of the Botanical Museum, atCopenhagen. By the courtesy of the Director we have beenenabled to examine certain of these and find that a number ofspecies of Sclerophoma are amongst them, but we have beenunable to identify any of these as S. Magnusiana. Lind (31) inhis description of Rostrup's herbarium has placed all thesespecimens under Phomopsis pitya (Sacc.) Lind. The identityof Lind's P. pitya (Sacc.) is discussed in a later paper (18).

Since the institution of the genus Sclerophoma by von Hohnela number of papers have appeared dealing with the origin ofthe spores in this genus. In his original description, vonHohnel (27) stated "Sporen... durch schleimige Histolyse desKerngewebes entstehend.' In a later paper (28) he furtherdescribed the production of spores by cleavage within ,a pri­mordial cell, "Conidien im innern der hyalinen Zellen einzelnoder zu mehreren gebildet, ... .' This endogenous spore originhas been further investigated in Sclerophoma pityophila (Cda.)v. Hahn. by van Luyk in 1923 who is not in agreement with themethod of origin as described by von Hohnel. Van Luyk re­peatedly demonstrated that the spores of this species are formedby budding from the walls of the cells. Petrak in 1923 discussedthis problem, and in 1924 he again described the "Sclero­phomaceen " and, while admitting that certain genera of vonHohnel's "Endogenosporae " produce spores by buddingdirectly from the walls of the cells of the hymenium, yet he stillmaintains that certain groups reproduce endogenously in themanner stated by von Hohnel. Included in one of the endo­genous spore groups which Petrak retains is Sclerophoma pityo­phila, which van Luyk asserts, as stated above, produces sporesby the processs of budding. Archer (5) discussed the" endogenous

Phoma pitya Sacco and Phoma abietina Hart. 269

spore origin " controversy, and submitted further proof withregard to the production of spores by budding for PhomaAstragali Cooke & Hark. and Diplodina coloradensis Ell. &Everh. He could find no trace of endogenous spore origin . Thesefindings also hold true for S arcophoma Mirbelii (Fr.) v. Hohn.,Sclerophoma concaoiuscula (Ell. & Barth.) v.Hahn. and Dothichizaminor (Ell. & Everh .) v. Hahn.

Spore formation has been examined in Sclerophoma M ag­nusiana and we find that here the spores are budded off fromthe walls of the hymenial cells lining the cavity as described byvan Luyk for S . pityophila and Archer for other fungi of vonHohnel's Endogenosporae (PI. XIX, figs. 4, 5). We were unableto determine any endogenous formation of spores, although thismight possibly take place under certain physiological conditionsof growth.

THE IDENTITY OF PHOMA ABIETlNA HART.

In his original description of the fir bark disease (PI. XX,figs. 7, 8) Hartig (19 . 20 ) regarded the organism to which the" Einschnlirungskrankheit " of the smaller branches of silverfir is attributed, as a new species which he designated by thepreliminary name Phoma abietina. He did not state the sizeof the spores or sporophores, but he does describe the shape.ofthe former and the nature of the fruit-body in which these areborne. Prillieux and Delacroix (43) dealin g with apparently thesame fungus in France preferred to designate the fungus asFusicoccum abietinum. Prill. & Delacr. and gave a complete de­scription of the fungus. They identified their organism witha specimen sent them by Hartig from Germany. OriginallyPrillieux and Delacroix had regarded their fungus as Dothiorellapitya Sacco (42) but a little later upon comparison with thetype specimen of Saccardo's fungu s (Fungi Veneti Ser. IV, 5;Sylloge fungorum, III, 241) decided that they were dealingwith quite another fungus. We have not seen the type ofDothiorella pitya Sacco which is reported to occur on A bies andPinus Strobus in northern Italy but th e figure given in Saccardo'sFungi italici, tab. 1454 shows an organism with spores appar­ently quite distinct in shape and size and with different pycnidialstromata from those belonging to Phoma abietina. Mer (35)

stated that the French organism offers" assez de ressemblanceavec celles decrites et figurees par Saccardo." A further studyof the Italian organism may reveal a closer relationship with thenorthern species. The history of Phoma abietina and P. pityashows that the former fungus has been referred to by some in­vestigators by the title given originall y to it by Hartig, whilstothers prefer that given by the two French investigators.

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We have not seen the type specimen of Phoma abietina Hart.Apparently Hartig did not deposit an "Originalexemplar " atMunich. Nor have we seen the specimen from which Prillieuxand Delacroix originally described their fungus as Fusicoccumabietinum (Phoma abietina Hart.). We have, however, examinedthe following material*:

(a) Phoma abietina Hart. on Abies pectinata collected byProfessor Hartig in the Bavarian Forest. Specimen fromthe Forstbotanisches und pflanzenpathologisches In­stitut, Miinchen.

(b) Phoma abietina Hart. on Abies pectinata from Dr RobertHartig's pathological collection purchased by the RoyalBotanic Garden, Edinburgh, Scotland from Dr K. vonTubeuf. This specimen is probably at least a co-type ofHartig's original collection.

(c) Fusicoccum abietinum Prill. & Delacr.-fresh field materialfrom the silver fir forests of the Jura Mountains (PI. XX,figs. 7, 8).

(d) Phoma abietina Hart. on Abies pectinata from the Her­barium of P. Magnus, Institut fiir allgemeine Botanik,Hamburg.

.Upon examination of the German herbarium material, thesespecimens are found to resemble very closely the fungusdescribed in detail by Prillieux and Delacroix as Fusicoccumabietinum and that briefly described and figured by Hartig inr889 as Phoma abietina. There is no doubt that we have hadunder investigation the same fungus as that observed by boththe German and French investigators. For the most part thefruit-bodies are found to be distinctly multilocular (PI. XX,fig. 9) although occasionally smaller pycnidia are observed withonly a single chamber (PI. XX, fig. ro), or the cavity may bedivided by incomplete partitions. The wall is thin below butthickens towards the apex, the thickened portion consisting offuliginous pseudoparenchymatous cells.

The fruit-body of Phomopsis abietina is not superficial(PI. XX, figs. 9, ro) as in the genus Fusicoccum, i.e. Fusicoccumcastaneum Sacco (8), or F. putrifaciens Shear (54), wherein theirregularly chambered fruit-body upon maturity becomeserumpent or subsuperficiaI. While both the fruit-bodies of

* We are deeply indebted to the following for the privilege of examining thespecimens of Phoma abietina Hart. (Fusicoccum abietinum Prill. & Delacr.):

(a) Prof. F. von Tubeuf, Forstbotanisches Institut, Munich.(b) The Regius Keeper of the Royal Botanic Garden, Edinburgh, Scotland.(c) Professor O. Guimer, National College of Forestry, Nancy, France.(d) The Director of the Botanical Institute, Hamburg.

Phoma pitya Sacco and Phoma abietina Hart. 271

Fusicoccum and Phomopsis are ectostromatic in origin, in thegenus Phomopsis the tendency is to regard the fruit-body asbeing only partially erumpent and remaining more or lessincorporated with the upper layers of the cortical tissue inwhich it is embedded. Upon maturity the cone or cushion­shaped pycnidial stromata rupture the epidermis disclosing theprotruding apices of the fruit-bodies. Upon these apices exuda­tions of spores appear either as minute whitish mucilaginousdroplets or as coiled tendrils. With maturity these fruitingbodies tend to empty themselves and fall away along with bitsof the broken epidermis so that the surface of the canker appearsminutely pocketed with the discoloured bark tissue and basalremains of the pycnidial stromata. .

The multilocular condition of the fruit-body we consider tobe the result of the fusing of primordia to form a compoundstructure. These confluent primordia give rise to the composite,many chambered pycnidium, discussed by Archer (5) and figuredby Prillieux in his text-book (41), reproduced here in PI. XX,fig. 9, and also by Hartig (20), and Bohm (6). The pycnidia tendto be immersed in or incorporated with the cells of the outercortex and only the upper part becomes exposed by the ruptureof the superficial tissues. The spores, which are borne on per­sistent sporophores, are much larger as compared with thespores of Phomopsis Pseudotsugae and Sclerophoma Magnusiana,their range being 9'S-IS x 4-6jL, commonly 12-14 x 4-SjL;characteristically spindle-shaped with acute extremities, asym­metrical, or symmetrical as figured by Prillieux, by Hartig andby Bohm ; one, two or even three large guttules may be present."B" spores have not been observed either in the herbariummaterial or in the fresh canker material received from the JuraMountains. The latter afforded abundant typically fusoid spores,agreeing in size and shape with the herbarium specimens men­tioned above. Germination was readily secured in ordinary tapwater, the spores producing vigorous germ tubes originatingapically or laterally. The culture characteristics of this fungus,which show striking differences from those of P. Pseudotsugae,will be reported in a later paper.

For the reasons discussed above we propose to place thefungus in the genus Phomopsis; the name therefore becomes:

Phomopsis abietina (Hart.) Wilson & Hahn.Phoma abietina Hart. Lehrbuch der Baumkrankheiten, ed. II,

124, 1889; Dothiorella pitya Prill. & Delacr. (nee Sacc.), in Bull.Soc. Mycol. France, VI (1890), 98; Fusicoccum abietinum, Prill.& Delacr. tom. cit. p. 176; nee Phomopsis abietina Grove, in]ourn.Bot. LIX (1921), 16.

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Stromata thickly scattered subconical or subglobular, witha flattened base, seated upon and incorporated with the innerlayers of the periderm, with only the apex protruding; black,unilocular, 120-300 x 60-180J.L, or multilocular, tending tobecome unilocular with slender partial septa, 360-500 x 240­

380J.L; wall very thin below becoming much thicker above,fuliginous, becoming paler towards the hymenium, dehiscing atone ostiole ; spores hyaline, symmetrical or asymmetrical, uni­cellular, spindle-shaped with acute ends, 9"5-15 x 4-6J.L com­monly 12-14 x 4-5J.L with 1-3 guttules, extruding in a whitishtendril or drop; sporophores persistent, subulate, 10-15 xI·S-2J.L; B-spores not observed.

Authentic specimens of Phomopsis abietina have been identi­fied by the writers only from Germany and France, and onlyupon Abies pectinata; typical specimens have not been collectedin Great Britain.

We have not seen specimens of this fungus on the Douglas fir.Organisms closely resembling P. abietina have been collectedon the silver fir and other conifers in the British Isles and thesewill be reported upon in a subsequent paper. On account of thelarge importation of conifers from the continent into GreatBritain it is not unlikely that typical P. abietina is already hereon the silver fir. The specimen of Fusicoccum abietinum reportedas occurring on Abies Veitchii in the United States (4, 56), 192 2,

has been received through the courtesy of Dr H. C. Young, OhioAgricultural Experiment Station, Wooster, Ohio, and Dr HavenMetcalf of the Office of Forest Pathology, Bureau of PlantIndustry, United States Department of Agriculture. A criticalexamination of this fungus indicates that it is not P. abietinaand its identity will be discussed in a later paper. We have notseen specimens of Phoma abietina reported by Doidge (II) fromSouth Africa.

The combination Phomopsis abietina Grove was apparentlynot based on the fungus described by Hartig, and Prillieux andDelacroix; for Grove's description is derived from specimens ofPhomopsis on Pseudotsuga Douglasii from Perthshire (r7). Hisdescription differs considerably from that of the German andFrench authors of the continental fungus on Abies pectinata.Phomopsis abietina as used by the authors has quite a distinctsignificance and refers only to the fungus described by Hartig,and Prillieux and Delacroix.

The perfect stage of Phoma abietina has not as yet been deter­mined. Hartig (20) attempted to connect the fungus with Pezizacalycina by infection experiments but failed. Rehm (45) givesDasyscypha calyciformis Willd. as the perfect stage, but Schel­lenberg (52) maintained that the fungus belonged to another

Phoma pitya Sacco and Phoma abietina Hart. 273

Discomycete. Prillieux (41) did not mention the ascigerous stagefor Fusicoccum abietinum in his text-book and in 1907 Henry (24),

reported the perfect stage as still unknown. Some species ofDiaporthe may prove to be the perfect stage of this fungus.

RELATIONSHIP BETWEEN PHOMOPSIS PSEUDOTSUGAE WILSONAND THE FOREGOING FUNGI.

The above consideration of the identity of Phoma pitya Saccoand P. abietina Hart. demonstrates that these fungi may nowbe considered as quite distinct morphologically from PhomopsisPseudotsugae. This fungus was first described in 1920 (59, 60), andmore fully in 1925 (64) as a parasite of Pseudotsuga Douglasii. Itwas also found to attack Larix leptolepis (61, 63), L. europaea (64),

Pseudotsuga glauca (64), and Abies grandis (64). An account ofthe disease on P. Douglasii was given by Alcock in 1921.Recently the fungus has been found attacking the branches ofCedrus atlantica both in England and Scotland. On the Douglasfir it causes a die-back of young shoots (PI. XXI, fig. II) andproduces well-marked cankers on the older stems (PI. XXI,figs. 12, 13, 14).

The synonymy and relationships of Phomopsis Pseudotsugaehave already been discussed (7,64) and it was suggested byWilson that the species had been previously included withother forms by Lind under P. pitya, and by Grove underP. abietina. During the examination of Rostrup's herbarium aspecimen of P. Pseudotsugae on Abies pectinata collected inDenmark in 1892 was found. Very probably the specimens onPseudotsuga Douglasii described by Grove (17) as Phomopsisabietina are P. Pseudotsugae, for the description of the sporesagrees rather closely both in shape and size with the sporesof the latter fungus. Grove states that" they also agree withwhat Hartig says and figures," but this does not appear tobe so, for the spores figured by Hartig, as has already beenpointed out, are distinctly fusoid and the spore size is muchgreater in all respects. As in the silver fir bark fungus, "B"spores (64) have not been observed although P. Pseudotsugae hasbeen grown for several years in artificial culture on variouskinds of media, and the fruit-bodies obtained culturally, as wellas those produced in nature have been under constant ob­servation.

As some modifications have been found necessary in theaccount of the fungus an emended description is now given:

Phomopsis Pseudotsugae Wilson.Pycnidia densely distributed obpyriform or lenticular with

a flattened base seated upon and incorporated with the innerM. s. IS

274 T ransactions British My cological Society

layers of the periderm with only th e apex protruding, black,0'3-1 mm. in diam eter , unilocular (PI. XXI, fig. IS) or multi­locular (PI. XXI, fig. 16) tending to become unilocular withslender partial septa , texture everywhere several cells thickmore or less hyaline and tinged green below, thi cker and blackabove, opening at a definite ostiole ; spores hyaline unicellularelliptic-fusoid, extremit ies obtuse or subacute, 4'5-8'5 x 2-4fL,occasionally with small oil drops, sporophores subulate, 12-14 x1-2fL; " B" spores not observed.

Hab. on branches and leaves of Ps eudotsuga Douglasii,P. glauca, Larix europaea, L. leptolepis, Abies grandis, A. pecti­nata and Cedrus atlantica in Great Britain; also on PseudotsugaDouglasii in Ireland.

Phomopsis P seudotsugae has been found on PseudotsugaDouglasii in Denmark by Boyce in 1925, in the island of Born­holm, and was collected by the senior author on the samehost near Copenhagen the following year. Material of the funguswas also kindly forwarded by Dr C. A. Jorgensen from themainland of Denmark in 1926. Specimens of the Douglas firseriously injured by this species were also collected by Wilson,at Loo, Schovenhorst and Baarn in Holland in 1926. The treesshowed typical cankers and dying back of the young shoots ;both nursery stock and trees up to fifteen years old were attacked.During a recent visit to Scandinavia , Hahn (1927) observedP. Ps eudotsugae, in the coastal region at Sefteland, Norway*,seriously attacking blue Douglas fir iPseudotsuga glauca Mayr.).killing the terminal shoots and branches. The death of manytre es had been caused by this parasite. Through the cour tesy ofProfessor Lagerberg a herbarium specimen of a diseased shoot ofPseudotsuga Douglasii preserved among th e pathological collec­tion at the Skogshogskolan, Stockholm, Sweden, collected atVastergotland , South Sweden in 1917 and attributed to Phomapitya, was examined and identified as typical Phomopsis Pseu­dotsugae. Diseased Douglas fir shoots from Glusted, Jutland, alsoexamined through the courtesy of Magister Rostrup, Plantapa­tologisk Laboratorium, Copenhagen, were found to be infectedwith the same fungus. These recent findings extend the previ­ously known distribution of the Phomopsis disease of Douglas firbeyond the confines of Great Britain to the continent , includingHolland, Denmark, Norway and Sweden. For practical purposesit must also be considered as present in Germany, Belgium andFrance. .

* Ackno wledgment is made t o Professor Hagem , Botanisk Museum, Bergen ,and Mr Ivar Jerstad, Botanisk Museum, Oslo, for eve ry possibl e assistance inst udying the Phomopsis disease of Douglas fir in Norway.

Phorna pitya Sacco and Phoma abietina Hart. 275

SUMMARY.

During the last half-century considerable confusion hasexisted in the forestry and mycological literature concerning theidentity of Phoma pitya Sacco and P. abietina Hart., fungi re­ported as parasitic on the Douglas fir and other conifers.Recently a parasitic fungus Phomopsis Pseudotsugae on theDouglas fir (Pseudotsuga Douglasii) has been described occurringin Great Britain and on the European continent, which showedcertain close relationships, both morphological and physiological,with the two well-known fungi referred to above. A criticalstudy for the purpose of differentiating the three fungi was con­sidered highly desirable for purely scientific as well as practicalpurposes.

Phoma pitya Sacco was found upon the examination of thetype specimen to be a Sclerophoma. According to the rules ofnomenclature the name must be changed as there is alreadya Sclerophoma pitya (Thiim.) V. Hahn. and the fungus has beenfully described as Sclerophoma M agnusiana Wilson and Hahn.

Phoma abietina Hart. is now considered to belong to the genusPhomopsis and is called Phomopsis abietina (Hart.) Wilson andHahn. The name P. abietina should be applied only to fungiidentical with Phoma abietina Hart. and Fusicoccum abietinumPrill. and Delacr.

Phomopsis Pseudotsugae Wilson is distinct morphologicallyand physiologically from P. abietina. Culture studies have in­dicated sharp differences. P. Pseudotsugae is a true parasite ofthe Douglas fir and other conifers, killing the young shoots andterminals and forming a canker on the larger branches andtrunks. To P. abietina is attributed the cause of a canker­constriction of the smaller branches of Abies. The latter fungushas not been observed to occur on the Douglas fir, nor in GreatBritain. Sclerophoma M agnusiana is very probably only asaprophyte.

An extensive bibliography is given which indicates the con­siderable amount of observational data and investigation whichhas accumulated during the past fifty years concerning theforegoing coniferous fungi.

REFERENCES.. (I) ALCOCK, X. L. A Phomopsis disease of Douglas fir. Gard. Chron, LXIX

(1921). 45.(2) ALLESCHER, A. Fungi impcrfecti: in Rabenhorst's Kryptogamen-Flora.

VI. 1901.(3) ANON. Absterben der Triebspitzen bci der Douglastanne. In Fragen­

kasten. Mitt. d. deutsch. Dendrol. Ges. XXXI (1921). 329.(4) -- Fusicoccum abietinum (Hart.) Prill. and Del. on Abies Veitchii. Plant

Disease Survey, United States Dept. Agric., Bureau of Plant Industry,Supp. XXIX (1923). 395.

18-2

276 Transactions British Mycological Society

(5) ARCHER, W. A. Morphological characters of some Sphaeropsidales inculture. Ann. Myco!. XXIV (1926), 1-84.

(6) BOHM, B. Uber das Absterben von Thuja Mensiesii, Doug!. und Pseudo­tsuga Douglasii Carr. Zeitschr. f. Forst- u. Jagdwesen, XXVIII (1896),154-161.

(7) BOYCE, J. S. Observations on forest pathology in Great Britain andDenmark. Phytopathology, XVII (1927), 1-18.

(8) DIEDICKE, H. Die Gattung Phomopsis. Ann. Myco!. IX (I9II), 8-35.(9) -- Dothiopsis, Sclerophoma and Sclerotiopsis. Ann. Mycol. IX (I9II),

279-285.(10) -- Kryptogamen-Flora der Mark Brandenburg, IX (1912), 280.(II) DOIDGE, E. M. A preliminary check list of plant diseases occurring in

South Africa. Bot. Survey, S. Africa, Memoir VI, 1924.(12) FABRICIUS, O. Douglas- og Sitkagran. Saertryk af Dansk Skovforenings

Tidsskr. (1926), 484-7.(13) FARQUHARSON, C. O. Tree diseases due'to fungi. Additional Scottish

Records in 1910-11. Ann. Scot. Nat. Hist. (I9II), 240-1.(14) FORBES,A. C. Some diseases of conifers. Gard. Chron. ser. 3, XIX (1896),

553-4·(IS) GROVE, W. B. British Species of Phomopsis, Kew Bul!. (1917), 49-52.(16) --Sclerophoma pithya Died. New or noteworthy fungi, Pt VI. Journ.

Bot. LVI (1918), 292-4.(17) -- Phomopsis abietina Grove. Mycological notes, Pt v. Journ. Bot.

LlX (1921), 16-17.(18) HAHN, G. G. Phomopsis conorum (Sacc.) Died.-an old fungus of the

Douglas fir and other conifers. Trans. Brit. Myco!. Soc. XIII (1928), 278.(19) HARTIG, R. Eine Krankheit der Weisstanne. Sitzungsbericht des

Botanischen Vereins in Munchen. Bot. Centralb!. XXXVII (1889),78-79.

(20) -- Phoma abietina n. sp. Der Tannenrindenpilz. Lehrbuch der Baum­krankheiten, II Auf!. (1889), 124-6.

(21) -- Phoma abietina n. sp. The fungus of the cortex of the silver fir.Diseases of Trees. English Trans. by W. Somerville and Marshall Ward.(1894), 138-g.

(22) HAUSRATH, D. H. Das Verhalten derin badischen Waldungen angebautenauslandischen Holzarten im Vegetationsjahr 1921-22. Mitt. d. deutsch.Dendro!. Ges. XXXIII (1923), 162-3.

(23) HENRY, E. La maladie du sapin dans les forets du Jura. Compt. Rend.Acad. Sci. CXLV (1907), 725-7.

(24) -- Le champignon de l'ecorce du sapin Phoma abietina R. Hartig (Fusi­coccum abietinum PI. et Del.) dans Ie haut Jura. Bul!. Soc. Sci. Nancy,ser. 3, VIII (1907), 361-378.

(25) -- La maladie du rouge dans les sapinieres du Jura. Ann. Forest., Rev.Eaux et Forets, XLVI (1907), 673-682, 705-710.

(26) HICKEL, R. Parasites; Ie sapin de Douglas. Bull. Soc. Dendro!. France,XLIV (1922), 74-75. ..

(27) HOHNEL, F. VON. Uber einige Phoma-Arten auf Nadelholzern, Frag­mente zur Mykologie. Sitz. Kais. Akad, d. Wiss. Wien, Math.-nat. K!.CXVIII, Abt. I (1909), 1230-4.

(28) -- System der Fungi imperfecti Fucke!. Falck's Myko!. Unters. undBerichte, I, Heft 3 (1923), 3°1-369.

(29) KONING, M. DE. Boschbescherming de leer der ziekten en beschadigingender houtgewassen, p. 160. Zutphen, 1922.

(30) LEVEN, G. Phoma pithya. A fungus on the Douglas fir. Trans. Roy. Scot.Arb. Soc. xv (1896-8), 319-320.

(31) LIND, J. Danish Fungi. 1913.(32) LINDAU, G. In Sorauer's Handbuch der Pf!anzenkrankheiten. II (1908),

399·(33) LUYK, A. VAN. Uber einige Sphaeropsideae und Melanconieae auf

Nadelholzern. Ann. Mycol. XXI (1923), 133-142.(34) MAUBLANC, A. Sur la maladie des sapins produite par Ie Fusicoccum

abietinum. Bull. Soc. Myco!. France, XXIII (1907), 160-173.

Phoma pitya Sacco and Phoma abietina Hart. 277

(35) MER. E. Description d 'une maladie nouvelle des rameaux de sapin. Bull.Soc. Bot. France, XXXVII (1890). 38- 49. (Summary by R. F er ry, Rev.Mycol. XVII (1895), 25-29.)

(36) -- Recherches sur la maladie des branches de sapin , causee par IePh oma abietina R. H artig (Fusicoccum abietinum Prill . et Del.) . Journ. deBot. VII (1893 ), 364-375.

(37) -- Le Phoma abietina, mal adie parasitaire des branches de sapin(nouvelles rech erch es) . Ann. Forest ., Revu e des Eaux et Forets, XLVII(1908) , 609-621.

(38) NEGER. F . W . Die Krankheiten unserer W aldbau me, pp. 173-1 74 . 1924.(39) PE TRAK. F. Uber einige Sclerophoma-Arten auf Ko niferen. Mykolo­

gische Notizen, Ann. Mycol. XXI (1923), 264-8 .(40) -- Uber sicht und Kritik der bish er bekannt en Sclerophomaceen­

Gattungen. Mykologische Notizen. Ann. Myc ol. XXII (1924), 1-182.(41) PRILLIEUX, E. Mal adies des Plantes Agri coles, II, P aris (1897), 285-9.(42) PRILLIEUX, E. and DELACROlX, G. Note sur le Dothiorella pitya Sacco

Bull. Soc. Mycol. France, VI (1890), 98.(43) ---- Sur deu x parasites du sapin pectine: Fu sicoccum abietinum Prill.

et Del., et Cytospora Pina stri Fr. Bull. Soc . Mycol, France, VI (18go), 174-8.(44) PRILLIEUX, E . and MAUBLANC, A. La maladie du sapin pcctine dans Ie

Jura. Corn pt . Rend. Acad. Sci. CXLV (1907). 699-701.(45) REHM. H . Ascomyceten: Die Pilze Deutschl ands, Oes terreichs und der

Schweiz. I n Rabenho rs t's Kryptogarnen-Flora, III (1896), 835. .(46) ROSTRUP, E . Be re t ninger om Undersogelser, foret agne i 1884 og 1885

itolge Finansministeriet s Foranstaltning, a ngaaende Snyltesvampeangrebpaa Naaletraeer, saerligtde forskelli ge Fyrrearter, paa al\e Statsskov­distrikterne i J yll and. 1885.

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(48) - - Plantepatologi, pp. 561-9. 1902.(49) - - Bornholrns Svampe. Bot. Tidsskr. XXVII (l g06), 378.(50) SACCARDO, P. A. Michelia, 1. '1878.(51) - - Sylloge fungorum , 1882-1926.{52} SCHELLENBERG. H. C. Das Absterben der sibirischen T anne auf dem

Adl isb erg . Mit t . a . d. Schw eiz. Zentral anst, f. d . forstl. Vers uchs w, VIII(1905) , 274. .

(53) SCHWAPPACH , A. Ne ue re Erfahrungen iiber das Verhalten von Pseudo­tsuga Douglasii und Picea sitkainsis. Mitt . Deutsch . Dendrol. Ges . XVIII(1909}. 95-99. (Rev. in Centralbl. fiir Bakt. P a ra . und lnfekt. XXIX(19II).89-<)0.}

(54) SHEAR, C. L. Endrot of Cranberries. J ourn . Agr, Res. XI (191 7), 35- 41.{55} SOMERVILLE, E . Rep ort of the Honorary Consulting Cryptogamist.

Trans. Roy . Sco t. Arb. Soc . xv (r896-(8), 190- 2 .

(56) STEVENSON,] . A. F oreign Plant Diseases. A manua l of economic plantdiseases which are new or not widely di stributed in the United States.United States Dept. Agric. {r926}, 3.

(57) TUBEUF. K. VON. Einschniirungskrankheit der T annenzweige. Pflan­zenkrankheiten durch kryptogame Parasiten verursacht, pp. 482-3. 1895.

(58) -- Diseas es of Pl ants induced by Cryptogamic P arasites, pp. 465-7 .Eng. ed. by W. G. Smith . r 897.

(59) WILSON, M. A new di sease of the Douglas fir in Scotla nd. Trans. R oy.Scot. Ar b . Soc . XXXIV (1920), 145-9.

(60) -- A new sp ecies of Phomopsis parasitic on the Douglas fir . Trans. andProc. Bo t . Soc. E dinburgh. XXVIII {1920}, 47-49.

{61} --A newly-recorded disease of the J apanese la rch. caused by PhomopsisPseudotsugae. Trans. Roy . Sco t . Arb. Soc. XXXV (r 92r), 73-74.

(62) -- The diseases of the Douglas fir. T rans. R oy . Scot . Arb. Soc. xxxv(1921). 77-78.

{63} - - The occurrence of the Ph omopsis di sease of the Japanese larch inYorkshire. Trans . Roy. Scot. Arb. Soc. XXXVI (1922), II5-6.

(64) -- The Phomopsis disease of conifers . Bul\ . 6, Forestry Commission. 1925.

278 Trans actions British Mycological Society

EXPLANATIO~ OF PLATES XVIII-XXI.All th e figur es in Plates XVIII a nd XIX are of Sclerophom a Magnu sian a

comb . no v. and are made from t ype specimen material of Ph oma pitya Saccoon P IIllIS syluestris ,

PLATE XVIII .F ig. 1. Photograph of type spe cimen and label .Fig. 2. Drawing of fruit bodies. X 4 .

Fig. 3. Pycnidium in section showing its superficial position. X 200.

PLATE XIX.Fig. 4. Part of pycnidium in sec t ion showing wall, hym eniallayer and spores.

x 50 o.Fig. 5. Part of pycnidium showing thickened wall cells, hymenial layer and

spore origin by budding. x 2 0 00.Fig. 6. Spores. x 2000.

PLATE XX.All th e figures are of Ph omopsis abietina comb. nov. on Abies pectin ata from

Jura, France.

Fig. 7. Branch sho wing" Einschniirungskrankhcit." Natural size.F~g . 8. A simila r branch showing the swe lling a bove the constriction. X 2 .FIg. 9. A reproduction of the figur e of a multilocular py cnidium of Fusicoccum

abietinum given by Prillieux.Fi g. 10. A unilocular pycnidium. x 1 7 0 .

PLATE XXI.All the figures are of Ph omopsis Pseudotsugae Wilson on Pseudotsuga Douglasii .

Fig. II . Four-year old t ree with leading sho ot killed.F ig. 1 2. Four-year old tree attacked near ground level , Th e stem is consider­

ably swollen about the well- marked const rictio n.Fig. 13. Part of main stem near t he base of a tree eight years old . The base of

an infected lateral bran ch is see n in th e middle of the ca nker.Fig. 14. Part of the main stem of a tree six t een years old showing a canke r in

side view. An inf ect ed lateral branch is seen on the right; the callus t issueis w ry eviden t. The dead bark hearing the sma ll black pycn idia is aboutt o be cast off.

F ig. 15 . Unilo cular pycnidia; one on the left and two on the right.Fig. 16 . A compound pycnidium.

PHOMOPSIS CONORUM (SACC,) DIED.-ANOLD FUNGUS OF THE DOUGLAS FIR AND

OTHER CONIFERS.By Glenn Gardner Hahn, B.Sc., M .Sc.

(From the Mycological Department, University of Edinburgh.)

(With Plates,XXII, XXIII)

INTRODUCTION.DURIl\G the investigation of cert ain of the fungi occurring onthe Douglas fir (Pseudotsuga Douglasii Carr.) closely related toPhomopsisPseudotsugaeWilson, Phomopsis conorum (Sacc.) Died.was observed in Great Britain on this host, which apparently hasnot been heretofore recorded. On account of its frequ ent occur-

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