160 Transactions British Mycological Society

under favourable conditions of humidity and temperature and developinto circular to irregular discoloured areas c. 2-3 mm surrounded by ayellow halo, 2-3 days after inoculation. Subsequently the central partsturn brown and necrotic with light yellow margins. The first sporulationwas noticed after the 4th day.

We are indebted to Dr V. P. Rao, Entomologist-in-charge, Common­wealth Institute of Biological Control, Indian Station, Bangalore, for hiskeen interest in these studies and to Mr F. C. Deighton, CommonwealthMycological Institute, England, for his advice concerning the identity ofthe fungus. To Dr H. Santapau, Director, Botanical Survey of India, weare grateful for the Latin version of the diagnosis. This research has beenfinanced in part by a grant made by the United States Department ofAgriculture under P.L. 480.

T. R. N. RAJ and K. M. PONNAPPA, Commonwealth Institute ofBiological Control, Indian Station, Bangalore, India

EXPLANATION OF PLATE I IRamulispora zonata

A, Leaf spots on Potamogeton nodosus viewed from the upper surface;B, from the lower surface, x c.I·5. C, sclerotia from a 4-month-old culture, X 100.

TRICHOCLADIUM PYRIFORMIS SP.NOV.

Trichocladium pyriformis sp.nov, (PI. 12, Text-fig. I)Coloniae in agaro 'malt' dicto diametrum attingentes 9 em viginti uno diebus,

circulares et in summo agaro creverunt. Chlamydosporae amplae factae, coloniae nigraevidebantur; facies versa coloniarum, sed non agarum, nigra erato Hyphae superficiales,ramosae, septatae hyalinae adulescentes quae maturitate fulvae fiunt, latae 0·7-4·5p.Chlamydosporae sessiles, propinque una spora cuique cellulae, facile diffunduntur cumomnino confinguntur; sporarum muri crassi levesque; sporae tri-cellulae, pellucidae cumjuvenes; maturitate, cellula ultima magna, fusca, praeacuta, cellula media fulva velhyalina, cellula proximahyalina, eamhyphaeconectens; 13'5-24 x 6-7'5 P (17.6 x 6'5 p).Chlamydosporae aliquando quadrococcae harum paucae habent cellulam proximamin culmum eductam. Nullae phialides notatae.

Habitat, in terra, Dublin, Eire. Typus IMI 93438; et in Schol. bot. Newcastle uponTyne.

Colonies on 2 %malt extract agar attained a diam of9 em in 2I days, werecircular and grew on the surface of the agar. They appeared black, due toabundant chlamydospore production; the reverse, but not the agar, wasblack. Surface hyphae, hyaline when young becoming yellow-brown withage, 0'7-4'5 It in width. Chlamydospores sessile, approximately one spore toeach' cell', readily shed when fully formed; spore walls, thick and smooth;spores, three-celled, hyaline when young; when mature, distal cell large,dark brown, pointed, middle cell pale brown to hyaline, proximal cellhyaline attaching it to the hypha; 13'5-24 x 6-7'5 It, mean (100 spores)17,6 x 6'5 It. Chlamydospores occasionally 4-celled, some having theattachment cell prolonged into a stalk, No phialides were observed. TypeIMI 93438; and Botany Department, University ofNewcastle upon Tyne.

This new species was isolated from one of eight soil samples taken from aTrans. Br. mycol, Soc. 51 (I), Printed in Great Britain

Trans. Br. mycol. Soc. VoL 5 I. Pla te I I

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(Facing. p. 160)

Notes and Brief Articles 161

Phoenix Park, Dublin, during an investigation offlower bed in thethermophilic fungi.

The soil was stored overnight in a refrigerator (5 °C). Samples of 5 g ofsoil were suspended in 45 ml of sterile water in 100 ml Ehrlenmeyer flasksand heat treated. Each flask was plugged and the contents vigorouslyshaken for I min before being placed in a constant temperature waterbath set at 80 °C. The soil solution took 10 min to reach 80 °C and was

e

d

Text. fig. I. Structure ofchlamydospore of T. pyriformis grown on Czapek-Dox agar. Thepigmentation is not shown, but the clear wall area is indicated in the proximal cellswh ere visible.

then left for a further 30 min at this temperature. Every 10 min the solu­tion was shaken for 30 sec. After treatment the flask was cooled byplunging into ice cold water for 15 min and finally shaken to obtain auniform suspension. Samples of 1 ml were then transferred to sterilePetri dishes and 3 % Czapek-Dox agar (CDA) containing 0'1 % yeastextract, adjusted to pH4, added. Ten plates ofeach sample were incubatedat 22°. After 4 days two colonies were observed on one plate only and thesewere transferred 6 days later to 2 % malt-extract agar (MA).

Abundant chlamydospore production on MA gave the colony a blackappearance. The colony filled the plate in 21 days, was circular and grewon the surface of the agar. The septate mycelium was hyaline when youngbut became yellow-brown with age. It was made up of hyphae 0'7-4'5 Itin width.

Enormous numbers of chlamydospores were attached directly to thehyphae, approximately one spore to each ' cell ' (PI. 12, Figs. I, 2): theywere readily shed when fully formed. No phialides were observed.

The chlamydosp ore walls were thick and smooth (Text-fig. I). TheTrans. Br. mycol, Soc. 51 (I), Printed in Great Britain

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162 Transactions British Mycological Society

majority of the spores were 3-celled and hyaline when young. Whenmature the spore was made up ofa large, dark brown, pointed distal cell, apale brown-to-hyaline central cell, and a hyaline proximal cell attachingit to the hypha (PI. 12, Fig. 3).

There were two principal types of variation in spore structure: somewere 4-celled having three pale cells (Text-fig. I, f, g); others had theattachment cell prolonged into a stalk (Text-fig. I,f, g). The presence ofaseptum in the dark cell was occasionally observed (Text-fig. I, e). A palearea was present at the apex of the distal cell (Text-fig. I); this can act as agerm pore but germination is not restricted exclusively to this area.

Growth of the isolate on CDA was thin but filled the plate in 15 days.The colony was black due to abundant chlamydospore production. Themycelium was hyaline becoming yellow with age. Variation in sporestructure was comparatively rare; an occasional stalked spore wasobserved. The spores were similar to those produced on MA, but themiddle and proximal cells were both hyaline. The spores were notreadily detachable.

The heat resistance of the spores was investigated. Spores from bothmedia were dry and, in order to wet them more effectively, they weretreated with aqueous sodium lauryl sulphate (I: 10 000) solution.

Temperatures of 75, 85, 95 and 100°C were selected. Test tubes con­taining sterile water were heated for 10 min in constant temperaturewater baths heated to the temperatures selected. One ml of the sporesolution was added and the temperatures maintained for a further 10 min.The solutions were then cooled in ice cold water and five 1 ml samplesfrom each were plated on to MA and incubated at 22°.

Spore germination was observed on the following day on all plates exceptthose containing spores treated at 100°. Five days later, many germinatingspores were observed on these plates, but their growth did not continue.

Spores were produced from colonies derived from heat-treated sporesafter 20 days. Spores of normal type were observed, but irregularities inspore structure were more common than in untreated samples. The sporesranged from completely hyaline to those with either a very pale brown ordark brown distal cell. The number of hyaline spores produced increasedin the colonies derived from higher temperature treatments. The numberof malformed spores was also greater in preparations made from coloniesderived from the 95° heated spores than from those treated at 75°.

It seems reasonable to conclude, therefore, that the fungus is thermo­philic since normal growth and some normal spores were produced aftertreatments up to 95°.

The known species of T richocladium Harz have been described recentlyby Hughes (1952) who designates 'Trichocladium asperum n.sp. [syn]Sporidesmium asperum Crd. (?)' as the lectotype. The newspecies issimilar toT. asperum in that it was isolated from soil and the conidia are constrictedat the septa. It resembles the remaining members of the genus in havingsmooth walled spores with pale areas at the apices. In Table I, thecharacteristics of the known species are compared. It will be noted thatapart from its smaller spore size, the shape and pigmentation of the spore

Trans. Br, mycol. Soc. 51 (r), Printed in Great Britain

Table I. Characters oj described species of Triehoc1adium (based on details in Harz, 187I ;

Hughes, 1952, 1959; Meyers & Moore, 1960)

~T. asperum. T i opocum T. tenellum T. canademe T . achraspora T. pyriformis

~Conidiophore Poorly Sessile, similar Forked, hyaline Present or Present or absent, Present or absent,

differentiated, to T. asperum absent pale yellow or not forked

~rarely forked, fuscous, nothyaline to forked

~~ subhyalinel3 Spore ...r- (l)

Size 12-28p; x IQ-15P; 2Q-4op;x IO'5-16 p; 7 '2 p; 12-18 Jl x 5- 12 p; 17- 21 P;X l O X 13 Jl 13' 5-24 u »: 6-7 '5 P. '"~~ Septal constriction Slightly Similar to Similar to Similar to Conspicuously Conspicuously ~UI constricted at T. asperum T. asperum T. aspenan constricted constricted.. the septa at septa a t septa tx:l........~

Shape Subglobose- Ellipsoid or Oval Oval -broadly Pyriform- Pyriform ;:I.~

~globose clavate clavate clavate- ~

s: oblong :A.~ Apex Rounded at Similar to Similar to Similar to Similar to Pointed at ~"'- T . asperum T . asperum T. asperum T. asperum ...S· apex apex o'c;') Apical pore Not known Not known Not known Pale area Not known Pale area ~~ at apex at apex '"e- No of cells ]- 3-ceIled, I-s-celled 2-celled Infrequently 2- s-celIed, Mostly 3-celledtl:l::I. mostly 2 r-celled, some mostly 3-4-~ 3-s-celled celledS· Wall Thick walled, Smooth walled Smooth walled Smooth walled Smooth walled Smooth walled

coarsely warted

Substrate from which Wood Wood and soil Wood Wood Wood Soilisolate was made

......N I-l

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164 Transactions British Mycological Society

provides a diagnostic feature enabling T. pyriformis to be recognized asdistinct.

A culture of T. pyriformis has been placed in the Herbarium of C.M.I.indexed as IMI 93438, and also in the Botany Department of the Uni­versity of Newcastle upon Tyne.

My thanks are due to ProfessorJ. H. Burnett of the Botany Department,University of Newcastle upon Tyne; to Dr M. B. Ellis of C.M.I. and toDr M. Stuart, under whose supervision this work was initiated at theBotany Department of University College, Dublin, Ireland.

REFERENCES

HARz, C. O. (1871). Einige neue Hyphomycete. Bull. Soc. imp. Moscow 44,125-127.HUGHES, S. J. (1952). Trichocladium Harz. Trans. Br. mycol. Soc. 35, 152-157.HUGHES, S. J. (1959). Microfungi. IV. Trichocladium canadense nov. sp. Can.]. Bot. 37,

857-58.MEYERS, S. P. & MOORE, R. T. (1960). Thalassiomycetes II. New Genera and Species

ofDeuteromycetes. Am.]. Bot. 47, 345-349.

MARJORIE DIXON (nee DAIN), formerly Department ofBotany,University of Newcastle upon Tyne

EXPLANATION OF PLATE 12

Trichocladium pyriformis

Fig. 1-3. Chlamydospore form ation of Czapek-Dox agar. Fig . I , x 4'4; fig. 2 C, x 286; fig. 3,showing difference in pigmentation ofcells and mode of attachment, a pale pore is visible on onechlamydospore (p), c. x 800.

CERCOSPORA NYCTANTHIS SP.NOV. ON NYCTANTHES ARBOR-TRISTIS

A severe leaf blight of Nyctanthes arbor-tristis L. (Verbenaceae) wasobserved from the winter of 1963-64 onwards in Borbheta, Assam, India.The same malady had also been observed at Kahikuchi, Gauhati. Thedisease first starts as one to a few round yellow spots soon turning tobrown with a yellowish halo at the beginning which increases in sizeblighting the whole lamina. On the under surface of the leaves, especiallyunder humid conditions, greenish grey fructifications develop. During the1963-64 winter more than 90 % of the leaves were affected causingsevere defoliation.

The pathogen has been identified as an undescribed species of Cercospora.In a personal communication to the author Mr Deighton of Common­wealth Mycological Institute states ' this IS the same as the collection onNyctanthes arbor-tristis from Indonesia which Boedijin wrongly identified asCercospora puttemansii P. Henn. '. The following is a brief description of thefungus.

Cercospora nyctanthis sp.nov. (Fig. 1)Maculae luteae cito evadentes brunneae ad 6 cm diam. halone lutea in foliis

causantes infectionem et abscissionem. Conidiophora evoluta e stromate, hypophylla,Trans. Br, mycol. Soc. 51 (I), Printed in Great Britain