T H E S L I M E M O U L D S O F D E L H I - I

by

HARDEV SINGH & K. K. PUSHPAVATHY

Department o/ Botany, University o/ Delhi, Delhi 6, India

(with 3 figs.)

(27.VIII. 1964)

The pioneering attempts on the description of Indian slime mmalds were those of LISTER (1924), BRf)HL & SEN GUPTA (1927) and LODHI (1934). However, for the following 20 years this group received scant attention. AGNII~OTHI~UDU (1954) and THIND et al. (see THIND & SOHI, 1955) revived the interest in this group. Their collections were made mainly from the hilly or wet regions like Mussoorie and Assam tea estates. So far, only a few attempts have been made to explore these fungi from the plains especially the dry areas like Delhi. The paucity of information on the Myxomycetes of Delhi may also be judged by the fact that Mthough a list of the fungi of Delhi (CHONA et al., 1958) has been compiled, slime moulds have not been included in it. The present paper describes 8 species of this group collected from Delhi during September-October, 1963.

The slime moulds occur in Delhi only during the short rainy season (July-October). They can be found growing on the plant debris in shady places soon after a couple of continuous and pro- longed showers.

The specimens were preserved by sticking them with rubber solution to the floor of cardboard boxes. Tile spores were studied after mounting them in lactophenol. To bring out the details of the capillitial threads of the Trichiales, they were stained in safranin and mounted in glycerine. The lime nodules and lime crystals of the Physarales were mounted in water, because the lime dissolved in other mounting media. For the details of capillitial net work of the Stemonitales, the material was dried at 56°C for 15 mimltes, passed through xylol and mounted in canada balsam.

The specimens have been deposited in the Herbarium Crypto- gamiae Indiae Orientalis, New Delhi.

Four species of the Physarales, Physarum bivalve, Didymium squamulosum, D. nigripes and Diderma hemisphaericum; two of the Stemonitales, Stemonitis /lavogenita and Comatrieha pulchelIa; and Mycopathol. e± Mycol. Appl. XXVlI, 1-2 3

3 ~ : H. S tNGH ~ K. K. PUSHPAVATHY

two of the Trichiales, Perichaena vermicularis and Arcyria oerstedtii have been described. Of these the last one is a new record for India.

1. Physarum bivalve PERS.

The fructification is a plasmodiocarp comprises of irregular sessile sporangia (Fig. 1A). I t is somewhat laterally compressed and 0.5 mm wide. The peridium is distinctly double; the outer one is thick, light yellow and calcareous; the inner one cinereous and thin. During the dehiscence, the outer peridium becomes reflexed and the inner one shows a longitudinal slit thus exposing the spores and lime nodules which are round, oval or irregular (Fig. 1B). The capillitial threads are hyaline and narrow with somewhat swollen ends. The spores are minutely spinulose, light brown and measure 6.6--8.2 # in diameter (Fig. 1C). It is commonly found on the dried leaves in the University campus and the Delhi Ridge. Our specimens closely match with the description given by THIND & SOHI (1955) of this fungus collected from the Mussoorie Hills.

2. Didymium squamulosum (ALB. & SCHW.) FR.

The fructification generally consists of distinctly stalked spo- rangia (Fig. 1D). Sometimes the sporangia are sessile and rarely a plasmodiocarp is seen. The sporangia are gregarious and white. They dehisce irregularly (Fig. 1E). The total length of a stalked sporangium varies from 0.25 to 0.3 ram. The stalk is white or cream- coloured and ridged. The stalked sporangium has a prominent hypothallus which shows finger-like branches spreading on the substratum (Fig. 1F). However, THII;D & SOHI (1956) mention that the hypothallus is indistinct. The peridium is covered over by a white powdery coating of stellate lime crystals (Fig. 1G). Our collection does not show the breaking of the peridi~m into scales as described by AGNIHOTHRUDU (1956). The columella is conspicuous (Fig. IF) and snow-white. The capillitium consists of hyaline and branched threads which are free from each other (Fig. 1H). However, THIND & SOHI (1956) have described the capillitial threads as united and the col~mella as brown in colour. The spores are dark purple, strongly warted, have an angular o~tline and measure around 10 # (Fig. 1I).

According to MACBRIDE & MARTIN (1934) this is a very variable species. It has been found to be quite true. The specimens collected from the same locality show considerable variations in size and nature of the fructification. In some collections the sporangium is large with a prominent stalk and hypothallus, in others the spo- rangium is small and sessile. Some of the sporangia are much smaller and show a wrinkled peridJum. These are probably degener- ated or underdeveloped sporangia, since they do not dehisce and on CnlShing them, one finds that the spores do not separate from each other. However, they have the typical colllmella and the

SLIME MOULDS OF DELHI I 3~

capillitium. It was collected from the University garden, Delhi, and is quite common.

PHYSARUM BIVALVE

•

DIDYM IUM NIGRIPES

DIDYMIUM SQUAMULOSUM

@

G

DIDERMA. HEMISPHAERICUM

. . . . . 0

Fig. 1A-Q. Order Physa ra les . A-C. Physarum bivalve. A. Dehisced f ruct i f ica t ion. × 10. ]3. Capill i t ial t h r e a d s and l ime nodules . × 633. C. spores. × 633. D - I . Didy- mium squamulosum. D. A c lus te r of u l ldehisced sporangia . × 15. E. Dehisc ing sporangia . × 15. F. Pe r s i s t en t s t a lk showil lg columel la a t t he top and wel l -developed h y p o t h a l l u s below. × 15. G. L i me c rys ta l s f rom t he pe r id ium. × 633. H. Capil l i t ial th reads . × 633. I. spores. × 633. J -M . Didymium nigripes. J. I n t a c t spo rang ia showing hypo tha l lu s , x 27. K. L i me crys ta l s f rom the pe r id ium. × 633. L. Capil- l i t ial t h r e a d s w i t h bead- l ike conf igura t ions . × 633. M. Spores. × 633. N - Q . Diderma hemisphaericum. 1",1. Dehisced and i n t a c t sporang ia as seen f rom t h e top. × 15. O. S ta lked s p o r a n g i u m in la teral view. × 15. P. Capilli t ia] th reads ; no te t h e H -

shaped joints . × 633. Q. Spores. × 633.

3*

36 H. SIIqGH ~ K. K. PUSHPAVATHY

3. Didymium nigripes (LI~'x) FR. The sporangia are scattered, distinctly stipitate and hemispheri-

cal to globose (Fig. 1J). The total length of the sporangium is 0.6--1.0 ram; its diameter is around 0.3 ram. The sporangia in our collection are smaller than those described by T~IIND & Sore (1956). The peridium is umbilicate and white due to the powdery coating of stellate lime crystals (Fig. 1K). The stipe is erect or flex~ous, brown or brownish black, prominent ly ridged and broad at the base. The columella is globose, dark brown and conspicuous. There is a well-developed membraneous hypotkall~s. The capilli- t ium comprises of dark narrow threads which are freely branched and show abxndant bead-like swellings (Fig. 1L). AGNIt~OTHRUDU (1956) did not ment ion about these configurations. The spores are wafted, the warts being more concentrated at places (Fig. 1M). I t was collected on the dried leaves of grasses and the bark of trees, in the University campus. The fungus is not common.

4. Diderma hemisphaericum (BULL.) I-IoR~IEM. The fructification is sporangiate bxt sometimes plasmodiocar-

pous (Fig. IN). Tile sporangia are most ly sessile but a few have a broad stipe (Fig. 10). They are depressed above and each spo- rangium is around 0.6 m m in diameter. THIND & REHILL (1958) have described a well-developed hypotkallus but in our material the hypothal las is not distinct. The peridinm is double-layered; the ol~ter one is chalk-white whereas the inner one is light brown. The sporangia dehisce along the margin. The capillitimn is scanty, coloxrless and non-calcareous. The threads are freely branched and have H-shaped joints (Fig. 1P). The spores are mauve, very minutely warted and measalre 7--8 ,u ill diameter (Fig. 1Q). I t was found growing on the bark of the dead twigs of Broussonetia in the University Botanical Gardens. The species is not common.

5. Comatricha putchella (BAB.) t~OST. The sporangia are gregarious, ovoid or rolmd and distinctly

stipitate (Fig. 2A), 0 .4~0.5 m m long and 0.3~0.43 m m wide. The stalk is shining black aud very variable in length (0.2--0.58 nun). The sporangia have a distinct light brown and rotate hypo- thallus. The capillitial threads are very well-developed. They are dark brown and nearly uniform in their width having several free and straight ends (Fig. 2C). However, TIdieD & MANOCHA (1958) have described loops at the ends of the capittitiat threads. The stipe is continued into the prominent black columella which gradually narrows and finally merges with the capillitial threads (Fig. 2B). The spores are pale brown, wafted, round and measure 6.8----8.5/~. All the spores in a sporangium are not of the same size and shape (Fig. 2D). The fungus was collected from the University campus on the decaying leaves of Nerium. The species is not corn- m o l l .

SLIME MOULDS OF DELHI I 37

COMATRICHA ,,PULCHE LLA

!

STEMONITIS FLAVOGENITA

E

j '

k~

H

@ M

Fig. 2A-M. Order S temoni ta les . A - D . Comatricha pulchella. A. Group of sporang ia on t he s u b s t r a t u m , x 7.3. B. One s p o r a n g i u m magn i f i ed to show the columel la and capil l i t ial t h r e a d s h a v i n g severa l free s t r a i g h t ends. x 100. C. por t ion of a s p o r a n g i u m magni f ied , x 233. D. Spores showing m a r k e d dif ferences in size. x 633. E-1V[. Stemonilis/lavogenita. E. Sporangia] t u f t s on a leaf. × 0.3. F. A few

spo rang ia magni f ied ; no te t he c o m m o n hypo tha l lu s , x 4. G. A por t ion of t he per idiaI m e s h w o r k f rom t he sur face of t he s p o r a n g i u m , x 163. H. Po r t ion of the p e r i d i u m in opt ical sec t ion showing columel la and t he pla te- l ike expans ions . X 183. I. A por t ion of s t ipe showing t he h y p o t h a l l u s and a re t i cu la te pa t t e rn , x 43. J. F u s e d bases of two st ipes. X 43. K, L. T ips of eolumel la f rom di f ferent sporangia .

× 183. M. Spores. X 633.

38 H. S I N G H ~: K. K. P U S H P A V A T H Y

6. Stemonitis ]lavogenita JAItN The sporangia are gregarious, the sporangial tufts extending up

to 4 cm in width (Fig. 2E). They are chocolate brown, stipitate and subflexuous or erect (Fig. 2F). The total length of the sporangittm is 6 mm and the width 0.3--0.5 ram. The stipe is shining black, 2--3 mm long and is joined basally to the disc-like hypothalhts which is common to a cluster. Sometimes the stipe bifurcates and bears two sporangia. Occasionally the stipe looks like a reticulam in the middle (Fig. 21). Rarely a sporangium branches slightly above the middle. The joining of the stipes of two sporangia near the hypothallus region is common (Fig. 2J).

The stipe is continued into the cohlmella which gives out branches all along its length forming the peridial net work whose meshes are of variable sizes. There are polygonal plates at the junction of many of the threads (Fig. 2H). The maximum width of the peridial mesh on the surface of the sporangium is around 16 # (Fig. 2G). The cohtmella narrows gradltally and curves variously at the tip. In this respect it does riot tally with the description given by MACBRIDE & MARTIN (1934) who write that the columella ends abruptly. Often the Columella has membraneous projections at the tip (Fig. 2L). THIND & SEHGAL (1963) also noted the same feature and they described even the bifnrcation of the cohlmella. In many sporangia the tip of the columella was found to be funnel-like (Fig. 2K). The spores are violet in transmitted light, minutely wafted and 6.6--8.3 ,u in diameter (Fig. 2M). It was collected from the University campus on the living leaves of radish. The species is rare but due to the gregarious nature of the sporangia it could be collected in good quantity.

7. Perichaena vermicularis (Scow.) ROST.

The fructification is plasmodiocarpous and closely appressed to the substratum (Fig. 3A). The units of the fruiting body vary from small spheres to elongated, flexions, variously branched and slender structures. The plasmodiocarp is brownish yellow. The peridium is double and opaque; the inner one shows reticulate markings (Fig. 3B). AGNIHOTHRUDU (1956) described the inner peridium as a papillose membrane. The capillitial threads are abundant, freq~lently branched, distinctly spinulose all over, and show swellings at places (Fig. 3C). According to AGNIHOTttRUDU (1956) the capillitial threads are minutely warted and constricted. The spores are 10--12 ¢ in diameter, pale yellow under the micro- scope, mostly rounded but sometimes oval and distinctly verrucose (Fig. 3D). It was collected from the New Delhi Ridge on the stem galls of Acacia leucophloea (caused by Hapalophragmium). This particular specimen was found on attached but dead galls. This seems to be an unusual habitat for a myxomycete. The species is rare.

SLIME MOULDS OF DELHI I 3 9

PERICHAENA VERMICULARIS

A

ARCYRIA OERSTEDTll

Fig, 3A-G. Order Trichiales. A-E. Peri~haena vern~icularis. A. Plasmodiocarp. × 7, B. Surface of the inner peridium, × 950. C. CapillitiaI threads. × 490. D.

Spores X 950. E-G, Arcyria oerstedtii. E. Two sporangia, a pa r t of the stipe is joined at the base; also note the persistent peridium on the top of one of the sporangium. × 15. F. The calyculi and the stipes of several sporangia; the stipes are borne on a common structure . × 15, G. CapillitiaI threads enlarged, × 950.

H. Spores. × 950.

~ 0 H. SINGH ~ K. K, PUSHPAVATHY

8. Arcyria oerstedtii ROST.

The sporangia are cylindrical and stipitate. ]~.e stalk is pinkish, slender and straight or curved. Occasionally two sporangia arise from a single stalk (Fig. 3E). The sporangia measure 2.5--3.0 mm in length. At matur i ty they are greenish yellow with a reddish tinge. They get easily separated from the reddish brown funnel- shaped calyculus. MARTIN (194:9) mentions that the cup is shallow. The latter is shining, 0.3--0.4 mm wide at the opening and 0.3-- 0.5 mm in height (Fig. 3F). The capillitial threads occur in abun- dance. They are spiny all over and 3.3/~ in width (Fig. 3G). The spores are light yellow in a mass but pallid in transmitted light, and measure 6.6/~ in diameter. They are ttfick-walled and have 4 or 5 spiny projections (Fig. 3H). The peridium is evanescent but it frequently persists at the apex of the sporangia. The fungus was found growing on dead wood in the New Delhi Ridge. The species is not common. I t had so far not been described from India.

Our specimens closely match with Arcyria virescens G. LISTER (see MACm~IDE & MARTIN, 1934). However, according to MARTIN (1949), A. virescens is a doubtfflt species and probably represents the greenish phase of A. oerstedtii.

Acknowledgements We are grateful to Professor P. MAHESHWARI for advice and

encouragement. Thanks are due to Dr. V. AGNIttOTHRUBU for going through the manuscript and for suggestions. One of us (K.K.P.) is thankful to the authorities of the Council of Scientific & Industrial Research, New Delhi, for the award of a Junior Research Fellowship.

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Ind ian bot. Soc. 33: 177--181; I82~-188. AGNIHOTHRUDU, V. 1956. Some slime-moulds f rom southern India - - IV. J. Ind ian

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J. Dept. Sci. Calcutta Univ. 8: 101--122. CI~ONA, B. L., LALL, G. ~; KAKRIA, N. C. 1958. The fungi of Delhi. Ind ian Counc.

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