REFERENCES

PATOUILLARD, N. (1891). Bulletin de la Societe Myco-logique de France 7,178.

PuNITHALINGAM, E. (1980). eM] Descriptions of Patho-genic Fungi and Bacteria No. 634.

Notes and brief articles 341

I thank Dr H. K. Airy Shaw and Mr R. D. RABENHORST, G. L. (1851). Botanische Zeitung BerlinMeikle of Royal Botanic Gardens, Kew for useful 9,455·discussion on this matter. STAFLEU et al. (eds) (1978). International Code of

Botanical Nomenclature. Regnum oegetabile 97, 1-

457·TARR, S. A. J. (1955). The Fungi and Plant Diseases of

the Sudan. Commonwealth Mycological Institute,Kew.

TWO AERO-AQUATIC HYPHOMYCETES FROM MALAYSIA

J. WEBSTER AND R. A. DAVEY

Department of Biological Sciences, University of Exeter

During a visit to the University of Malaysia, KualaLumpur, in March 1978, the opportunity arose tosearch for aero-aquatic fungi on submerged treeleaves from tropical ponds and swamps. Two ofthem are the subject of this paper. One, Cancelli-dium applanatum, has already been described byTubaki (1975) from Japan. The other, Fusticepsbullatus, is the type of a new genus.

CANCELLIDIUM APPLANATUM Tubaki, Trans. Mycol.Soc. Japan 16:358 (1975). (Figs 1,2)

Propagules of this fungus appeared abundantly onsubmerged leavesof various trees from a wide rangeof localities, e.g. leaves and petioles of rubber(Hevea), and Dillenia suffruticosa and leaves ofdipterocarps collected in the grounds of the Uni-versity of Malaysia, and from Templer Park, a fewmiles from Kuala Lumpur. When such leaves areincubated in shallow water in large Petri dishes atroom temperature (25-30 "C) whitish propagulesdevelop at the air-water interface. Under a dis-secting microscope the propagules appear ratherlike a flattened wineglass with a stalk and a hollowcup. Each propagule arises from an erect, septateconidiophore. At its upper end the conidiophorebranches to form a series of closely appressedseptate hyphae, arranged in the form of a hollowcylinder (Fig. 1 A). As the propagule matures thetips of the hyphae curve inwards so that the hollowair-containing lumen becomes completely enclosed(Fig. 2). Mature propagules become darker andflattened and may be heart-shaped in outline. Theyare quite large, measuring up to 180 pm long andover 100 pm wide.

Cultures were readily established by picking uppropagules on a fine flamed sewing needle andstreaking them on to 0'1 % malt extract agar withadded antibiotic. Tubaki (1975) found that the

fungus fruits on oat meal agar, and he obtainedexcellent sporulation when he cultivated it onsterilized pieces of banana leaf placed on thesurface of com meal agar. In our cultures on agarthe fungus did not fruit. However, using thetechniques described by Fisher (1977a) forstudying aero-aquatic hyphomycetes, sporulationwas induced. Disks of beech leaves, Fagussyluatica, 9 mm diam were autoclaved in distilledwater in a conical flask. When cool, the disks wereinoculated with an agar block containing mycelium,and incubated at 25 ° for 21 days. The flasks wereshaken by hand at daily intervals to ensure spreadof the inoculum. When the disks were fullycolonized they were removed from the flask andincubated on moist sterile filter paper at roomtemperature (about 20°). Propagules developedwithin 5 days, and these are illustrated in Fig . 2.

As shown in Fig. 2 D, the propagules are non-wettable and, when placed at an air-water interfacethey accumulate at the meniscus, projecting intothe air .

Tubaki (1975) isolated the fungus from blocksof balsa wood (Ochroma pyramidale) submergedin Lake Sengari, Kobe, Japan. The demonstra-tion that the same fungus is present on sub-merged leaves in Malaysia suggests that it mayhave a wide distribution in suitable tropicalhabitats.

Specimens (dried Fagus leaf disks bearingpropagules) have been preserved in Herb. Exr.No . 3598, and duplicates have been deposited inthe Herbarium, University of Malaysia.

Fusticeps gen. nov.(etym. fustis: a knobbed stick, -ceps: head)Mycelium septatum, fuscum. Conidiophorae erectae,septatac, non-ramosae aut interdum ramosae. Conidia

Trans. Br, mycol, Soc. 7S (2), (1980). Printed in Great Britain

0007-1536/80/2828-6600 $00.35 iC" 1980 The British Mycological Society

342 Notes and brief articles

holoblastica, integrata, solitaria, fusca, transverseseptata, epispora fracta in squamas irregulares, quaecapiunt aera, Typus generum F. bullatus est.

Mycelium septate, dark. Conidiophores erect,septate, unbranched or occasionally branched.Conidia holoblastic, integrated, solitary, dark,transversely septate, epispore fractured intoirregular scales which entrap air.

Fusticeps bullatus sp. nov. (Figs 3,4)(Etym. bulla: knob, pimple)Mycelium fuscum, septatum, 2-4 pm diam, cum cellisglobosis intercalariis 10-15 pm diarn, tenui pariete, Incultura in 2 % malt extract agar fungus crescit lente,attingens 40 mm post 50 dies in 25°. Humile myceliumfuscum griseum vel atrum, velutinum in aere crescit.Conidiophorae erectae, non ramosae aut interdurnramosae, septatae, fuscae, 24-65 x 3 4 Jim, paulumconstrictae ad juncturern cum conidia. Conidia holo-blastica, integrata, solitaria, clavata, aspero pariete,fusca, cum 3-4 (plerumque 3) septis transversis. Cumseparatur cicatrix lata apparet,

In foliis subrnersis arboris ignotae, TemplerNational Park, prope Kuala Lumpur, Malaysia, menseMartio 1978. Specimen typicum in Herb. ExoniaNo. 3597 (Herb. IMI 245198) est.

A

Mycelium dark, septate, 2-4 pm diam, formingglobose intercalary or terminal thin-walled swel-lings 10-15 pm diam. In culture on 2 % maltextract agar the fungus grows slowly, reaching acolony diameter of 40 rom after 50 days at theoptimum temperature, 25°. A low-growing darkgrey to black velvety aerial mycelium develops.Conidiophores erect, unbranched or occasionallybranched (Fig. 3), septate, dark, 24-65 x 3-4 pm,slightly constricted at the junction with theconidia. Conidia holoblastic, integrated, solitary,clavate, rough-walled, dark, with 3-4 (usually 3)transverse septa, 28-34 x 9-12 pm. On detachmenta broad basal scar is visible.

Submerged leaves of an unidentified tree werecollected from a swamp in the Templer NationalPark, near Kuala Lumpur, Malaysia. The leaveswere rinsed in water and incubated at roomtemperature (25-30°) in a shallow layer of water.Within a few days the characteristic clavateconidia were seen under a dissecting binocularmicroscope. The conidia developed from conidia-phores projecting into the air. They appearedgreenish in colour due to air, trapped in theroughened extensions of the spore wall. Cultureswere readily established by picking off conidia with

"'.";

B

Fig. 1. Cancellidium applanatum: (A) Developing propagule; (B) propagule with tips of componenthyphae appressed.

Trans. Br, mycol, Soc. 7S (2), (1980). Printed in Great Britain

0007-1536/80/2828-6600 $00.35 © 1980 The British Mycological Society

Notes and brief articles 343

100 I'm'------ ---'

()

Fig. 2. Cancellidium applanatum: (A) Scanning electron micrograph of propagule seen from the side;(B) end view of propagule showingclosed apex; (C) two propagules mounted in water viewed by trans-mitted light; the dark contents indicate enclosedgas; (D) three propagulescaught at an interface betweenair (above)and water (below) showing their non-wettable nature.

a flamed sewing needle and streaking them on to0'1 % malt extract agar with added antibiotic. Aslowly-growing dark mycelium developed on 2 %malt extract agar. The optimum temperature forgrowth was tested at four temperatures within therange 15-30°. Although growth took place at alltemperatures, growth was very slow at 15°(colony diam 13 mm after 55 days) with anoptimum at 25° (colony diam 40 mrn after 55 days).Sporulation was not observed on the dry agarsurface, but if agar cultures were flooded withsterile distilled water and left covered with water,sporulation occurred when the water was drainedaway. Inoculation of sterilized beech leaf disksimmersed in water (as described above) alsoresulted in good sporulation when the disks wereincubated in moist chambers. It is in this formthat herbarium specimens have been preserved.

When leaf disks bearing sporulating colonies areflooded with water the spores which are non-wettable float away, and remain buoyant, presum-ably because of the air trapped between the flakesof the epispore. As with many aero-aquaticHyphomycete spores, the spores of Fusticeps canbe wetted, and brought into suspension by theaddition of 0'1 % Brij 35 (polyoxyethylene laurylether, B.D.H. Chemicals Ltd, Poole, England), adetergent, without affecting the capacity togerminate.

The characteristic feature of Fusticeps is theextension of the spore wall to form projectionswhich entrap air. Details of the projections werestudied by transmission electron microscopy.Mature spores grown on agar were fixed in 1 %OS04 and embedded in Araldite. They weresectioned, using a glass knife at a thickness of

Trans. Br, mycol. Soc. 75 (2), (1980). Printed in Great Britain

0007-1536/80/2828-6600 $00.35 © 1980 The British Mycological Society

344 Notes and brief articles

~

Fig. 3. Fusticeps bullatus: Conidiophores and conidia.

20 ,Ulll

about 80 mp,m. The sections were mounteddirectly onto copper grids and examined using anAEI 801 transmission electron microscope. Partofalongitudinal section of the apex of a spore is shownin Fig. 4D, and an enlarged part of the section inFig. 4E. The most conspicuous feature of thesurface ornamentation of the spores is the mush-room-shaped projections, whose heads are closelyappressed. Each projection consists of a cylindricalshaft with a wall which tapers from a thickerproximal part to a thinner distal part. The pro-jection expands to a dome-shaped, thin-walledcap. At present, we have no information about thecontents of the projections, but all seemed void ofcytoplasm and, since the contents are similar inappearance to the spaces which separate them, webelieve that they may contain air. It seems likelythat the buoyancy of the propagule may be due toair entrapped within the projections and alsobetween them (Figs 4B-C).

DISCUSSION

Interest in these two aero-aquatic fungi centres onthe methods by which they develop buoyant pro-pagules (Webster & Descals, 1980). This ecological

group of fungi has been defined by Fisher (1977b)as follows: 'Aero-aquatic fungi are indwellingorganisms characterised by the production ofpurely vegetative mycelium in substrata underwater and by the formation of conidia with aspecial flotation device, formed only when thesubstrate on which the fungus is growing isexposed to a moist atmosphere.' The flotationdevice may be a spirally coiled spore (e.g. Helicoon,Helicodendron), a clathrate sphere (Clathro-sphaerina), a dichotomously branched conidiumwith contiguous lobes (Candelabrum), a morula ofglobose cells separated by air-spaces (Aegerita,Beverwijkella), a morula of cells enclosed by in-curved spiny arms (Peyronelina), or a system ofincurved branches enclosing air (Spirosphaera).The two fungi discussed here illustrate differentsolutions to the same problem. In Cancellidiumthe flattened hollow closed propagule encloses agas-filled space. In Fusticeps the air is entrappedbetween mushroom-shaped projections whichdevelop from the spore wall, and possibly alsowithin the projections.

One of us 0. W.) is indebted to the Universityof Malaysia for an invitation to work there and to

Trans. Br, mycol. Soc. 75 (2), (1980). Printed in Great Britain

0007-1536/80/2828-6600 $00.35 © 1980 The British Mycological Society

Notes and briefarticles 345

UIII (

c

/-

. .

20 um

Fig. 4. Fusticeps bullatus: (A) Conidium attached to conidiophore. Scanning electron micrographshowing spore ornamentation; (B) conidia wetted to show the surface ornamentation; (C) non-wettedconidia showing air trapped between the surface projections; (D) L.S. conidium showing the projectionsfrom the spore wall; (E) Enlargement to show details of the wall projections.

Dr T. C. Chen and Professor A. Nawawi forproviding facilities in the Botany Department. Weare grateful to Mr H. W. Stubbs for providing theLatin diagnosis, and to Dr B. C. Sutton for helpfultaxonomic advice.

REFERENCES

FISHER, P. J. (1977a). New methods of detecting andstudying saprophytic behaviour of aero-aquatichyphomycetes from stagnant water. Transactions ofthe British Mycological Society 68, 407-411.

FISHER, P. J. (1977b). Ecological studies of aero-aquatichyphomycetes. Ph.D. Thesis, University of Exeter,England.

TUBAKI, K. (1975). Notes on the Japanese Hypho-mycetes. VII. Cancellidium, a new Hyphomycetegenus. Transactions of the Mycological Society ofJapan 16, 357-360.

WEBSTER, J. & DESCALS, E. (1980). The distribution andecology of conidial fungi in freshwater habitats. InThe Biology of Conidial Fungi (Ed. Cole, G. T. &Kendrick, W. B.). New York and London: AcademicPress. (In the Press.)

Trans. Br. mycol, Soc. 75 (2), (1980). Printed in Great Britain

0007-1536/80/2828-6600 $00.35 (C) 1980 The British Mycological Society