[ 3°9 ] Trans. Br. mycol, Soc. 59 (2),309- 311 (1972) Printed in Great Britain
AUSTRALIAN LEAF-INHABITING FUNGI III. OBSERVATIONS ON HARKNESSIA
By H.]. SWART School
ofBotany, University of Melbourne, Australia
Harknessia renispora sp.nov. is describ ed from lea ves of two species of Melaleuca, Two other species of Harknessia are recorded from hosts other than Eucalyptus.
The study of indigenous fungi in Australia is often hampered by the fact that many of the early collectors were visitors who took their material back home; consequently a great deal of type material is not available locally. Fortunately some of this material is being used for monographic studies, giving the basic information required for further studies of Australian material on th e spot. Such information on the genus Harknessia Cke has been provided in a recent monograph by Sutton (1971). This has made possible the evaluation of some collections of this genus mad e around Melbourne over several years. The outcome has been several interesting new host record s and one new species. Harknessia renispora sp.nov. Fructificationes copiosae, separatae, amphigenae, immersae, subspidermales, uniloculatae, erumpentes, ex hospite in amplitudine formamentoque variantes ; murus variabilis, ex pseudoparenchyma (muras tenues habenti) compositus, stratis interioribus hyalinis, in aliquot partibus exterioribus fulvidus; patefactio ex hospite va rians. Cellulae conidiogenae ex cellulis interioribus muri strornatis formatae, in partem tubulatam conidiiferam subito contractae. Conidia holoblastica, non septata, reniformia, 14-18 x 1012 X 9 pm, badia ; pars cellulae conidiogenae ut appendix cylindrata basalis hyalina persistens, sine protoplasma, 2- 6 pm Ionga, Typus, In foliis mortuis Melaleucae lanceolatae, Djerriwarrh Creek, Victoria, Australia, H.J. Swart, 2 1July 1970 (C.B.S. 153.71 ).
Fructifications abundant, separate, amphigenous, immersed, subepidermal, uniloculate, erumpent, varying in size and shape according to host; wall varying in thickness and colour, compos ed of thin-walled pseudoparenchyma, hyaline in inner layers, pale brown in some outer and upper parts; opening varies according to host. Conidiogenous cells formed from th e inner cells of the stroma wall, tapering abruptly to a conidiumbearing tubular part. Conidia holoblastic, aseptate, kidney-shaped, 1418 x 10-12 x 9 Jim, dark brown with part of the conidiogenous cell persisting as a cylindrical, hyaline, basal appendage devoid of cytoplasm, 2-6 Jim long. This species, easily recognized by its strongly asymmetric spores but otherwise a typical Harknessia, has been observed on two species of Melaleuca. On Melaleuca lanceolata the leaf structure has forced the fructification into an unusual shape. A cylindrical leaf subjected to internal pressure will
Transactions British Mycological Society
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Harknessia renispora. A, Fructification on Melaleuca lanceolata; B, fructification on Me/almea squarrosa; C, developing and mature conidia.
B C A, Harknessia uromycoides from Platylobium obtusangulum; B-C, Harknessia eucalypti; B, from Melaleuca squarrosa; C, from Leptospermum myrsinoides.
Australian leaf-inhabiting fungi. H. J. Swart
split longitudinally; consequently the fructification developed as a wedge, widening out beneath the lifted epidermis, and opening by a longitudinal slit. The fungus has been grown in culture on a tomato decoction agar and an oatmeal decoction agar. Here the fructifications were mor e or less globose and eventually opened widely; the spores were typical. Scattered fructifications of H. renispora have been observed on leaves of Melaleuca squarrosa mainly inhabited by Seimatosporium dilophosporum (Cke) Sutton. In these flat leaves a more regular development has taken place although the stroma is still somewhat restricted by the fairly compact palisade tissue, widening out beneath the lifted epidermis. One single fructification of a species of Harknessia was found on a leaf of Platylobium obtusangulum colonized by a species of Seimatosporium. The Harknessia is illustrated in Fig. 2A, its spore measurements are those of H. uromycoides (Speg.) Speg. As this species has so far been reported for Eucalyptus only, a record on a Legume is of special interest. Two further records of Harknessla are worth mentioning. One is on a specimen of Melaleuca squarrosa (Fig. 2B). Conidia measure 18-20 x 1214,um with an appendage 1-7,um long, and this and other aspects conform to the description of H. eucalypti Cke. In the old slide the inner membrane of the conidium wall appears to be quite thick; this, however, was not seen when the slide was freshly made. The evanescent mucilaginous sheath mentioned in Sutton's (1971) description of this species could not be observed. The other record is on Leptospermum myrsinoides (Fig. 2 C). Conidia look very similar to those of H. eucalypti and on some the remnants of a thin mucilaginous sheath are visible. Measurements are 14-19 x 1012 /lm; the very short basal appendage is rarely more than 3 ,urn long and may be reduced to a frill. These measurements fall almost below the range given for H. eucalypti, but as this species has so far been studied from only a few specimens, all on Eucalyptus, it may well have a greater range of variation than appears from the description. In one conidium a faint longitudinal pale area was noticed but in other conidia seen at the same angle this was absent. These records share as a special interest that they appear to be the first records of Harknessia in Australia on hosts other than Eucalyptus. The author wishes to thank Mr J. H. Willis, formerly of the National Herbarium, Victoria, for providing the Latin diagnosis, and Drs H. A. van der Aa of the C.B.S., Baarn, Netherlands, for helpful discussions. REFERENCE
SUTTON, B. C. (1971). Coelomycetes. IV. The genus Harkenessia and similar fungi on Eucalyptus. Mycological Papers 123, 1-46.
(Acceptedfor publication 4 May 1972)