An expanded concept of Armillaria luteobubalina

[ 75 ] Printed in Great Britain

Trans. Br. mycol. Soc. 77 (1) 75-83 (1981)

AN EXPANDED CONCEPT OF ARMILLARIA LUTEOBUBALINA By G. A. KILE CSIRO Division of Forest Research, Creswick, Victoria, Australia 3363 R. WATLING Royal Botanic Garden, Edinburgh, Scotland EH3 5LR AND

Armillaria luteobubalina is widely distributed in endemic eucalypt forest and woodland communities in south-eastern Australia and is considered to be native there. Basidiomes develop in the field from April to July, with most being produced in the second half of May. A report is given of the successful in vitro production of basidiomes, and variation in both field and cultured material is described. No significant differences in basidiospore form and size were evident between collections from different geographical areas. The host range has been expanded to 30 species, mainly from Myrtaceae and Mimosaceae, but two monocotyledonous hosts were recorded. Armillaria luteobubalina Watling & Kile was described from basidiomes collected at Dumbrell Block in the Strezlecki Ranges in eastern Victoria (Podger, Kile, Watling & Fryer, 1978). Macroscopically similar basidiomes collected from eastern Tasmania and the western highlands of Victoria were initially separated from A. luteobubalina by a number of criteria including their overall dimensions and basidiospore size. More detailed examination of these and subsequent collections from both the original and additional areas indicates that all the collections should be referred to A. luteobubalina. This report gives additional descriptive information on the species, hosts and distribution. Observations based on 75 basidiome collections were made over a five-year period (1974--9) in south-eastern Australia. DISTRIBUTION AND HABITAT

Basidiomes of A. luteobubalina were collected in Tasmania, Victoria and the Australian Capital Territory (Fig. 1). The limit of its northern distribution in eastern Australia is unknown, and it is not known from South Australia or Western Australia although superficially similar habitats are present in the former state. Armillaria luteobubalina has a scattered distribution in eucalypt forest and woodland communities within the 600-1300 mm rainfall zone, and between sea level and 900 m elevation. It appears to be absent from wet eucalypt forests (> 1300 mm rainfall) in lowland and upland areas and temperate rain forest communities. One locality in north-western Tasmania, at Woolnorth near Montagu with a rainfall ca. 1100 mm per annum,

is known where it occurs in a eucalypt-temperate rain forest community, although other species of Armillaria characteristic of the latter vegetation type (Kile, unpubl.) were also present. COLLECTION TIME OF BASIDIOMES

Basidiomes were collected from mid-April to midJuly, although 58 % of the collections (1974--9) were made in the latter half of May (Fig. 2). Although there is some bias in interpreting the data on the dates of basidiome collection as an indicator of in vivo basidiome production, in that collecting was more intensive when it was apparent basidiomes were available, the notable constancy in the time of basidiome production from year to year in many locations and the limited period (4-10 days) that expanded basidiomes remain in good condition, indicates that the normal annual peak of basidiome production occurs about the time suggested by Fig. 2. On a local or regional basis there was some evidence that the annual peak of basidiome production was influenced by environmental conditions. For example, because of the dry autumn in western Victoria in 1976 most basidiomes developed in that region in late May and the first half of June, whereas in 1979 with early autumn rains, basidiomes were collected from mid-April and were abundant from early May onwards. Initiation of basidiomes after June was rare and the only collections made in July were of overmature material. Basidiomes collected in early winter sometimes had abnormally thickened pilei and stipes, and severe winter frosts caused rapid deterioration.

Armillaria luteobubalina

NEW SOUTH WALES

Tidbinbillr'! VACT • Tallangatta VICTORiA s\ord

~"I\e

Mt Cole. ~. Trentham Creswick. • Mt Macedon

~,

.......

,

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Fig. 1. Known distribution of A. luteobubalina in south-eastern Australia.

BASIDIOME MORPHOLOGY

The following information on macroscopic characters is offered to supplement that published previously (Podger et al., 1978), the most significant modification being that the size range exhibited by basidiomes of A. luteobubalina has been greatly extended.

Pileus 40-100(-150) mm diam, at first convex with strongly inrolled margin finally becoming expanded and subumbonate to umbonate, occasionally becoming concave, sometimes carnpanulate and radially fissured with age, citrine to mustard yellow sometimes with a mottled zone around the margin with age; centre squamulose and characteristically darker with yellow hues

G. A. Kile and R. Watling

77

30 c: 25 '"

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~

20

<0

15

"0 u

... .0 "

E

i-

10 5 0

2

2

3

4

May

Fig.

2.

Frequency distribution of seventy-five A . luteobubalina basidiom e (D ivisions represent quartiles of months.)

dat es, 1974--9.

4 Fig. 3. Floccules on the undersurface of the ring and stages of ring development in A . luteobubalina. Fig. 4. Hemispherical-carnpanulate basid iomes of A . luteobubalina from Da ylesford, Victoria . Fig . 5. Darker and more densel y squamulose basid iomes of A . luteobubalina, Victoria Mill Scenic Reserve, Mount Cole State Forest, Victoria.

Armillaria luteobubalina

Fig. 6. Smooth-walled basidiospores of A. luteobubalina (SEM, collection 114) x 2625. Fig. 7. Wall structure of A. luteobubalina basidiospores (TEM, collection 208) x 9100. more noticeable towards the margin, sometimes relatively uniform throughout and finally often ferruginous or dark rusty brown; scales adpressed only some distinctly sub-erect, dark brown or olivaceous black and becoming honey brown at disk with age, yellowish or olive towards the margin, occasionally ornamented by velar fragments. Stipe 40-120(-125) x 7'5-15(-25) rnm, central, tough but cartilaginous, solid, slightly thickened towards the base and often elongated particularly when densely clumped, pinkish white at apex becoming brownish and often dark olivaceous towards the base, when young often with yellowish floccules dispersed below the ring and cortical tissues more or less splitting laterally or longitudinally; annulus at first whitish on the upper surface with concentric zones of ochraceous yellow or yellow-olive floccules on undersurface (Fig. 3), later becoming more uniformly flushed yellow. The characters of both the lamellae and the flesh for the recent collections were consistent with the original material.

INFLUENCE OF GENETIC AND ENVIRONMENTAL FACTORS ON BASIDIOME MORPHOLOGY

Field observations have illustrated the importance of both genetic and environmental influences on the morphological variation of the basidiomes of A. luteobubalina. In the absence of exceptional environmental conditions, morphology was recognizably consistent from year to year at anyone location. Thus in Victoria hemispherical-campanulate pilei (Fig. 4) were typical of material from Daylesford (pinchgut Road coli. 206 , 303) and collections from Creswick (Shuttleworths Road colI. 111,201) were distinguished by the relatively small and strongly umbonate pilei. Specimens from Mount Cole State Forest (Victoria Mill Scenic Reserve coli. 110, 317-323) were usually more den sely squarnulose, darker and more uniform in colour (Fig. 5) than material from other areas, whereas

G. A. Kile and R. Watling those from east Trentham (coll. 113) exhibited the greatest intensity of yellow. Growth habit, which is also presumably under genetic control, affected morphology. Basidiomes produced singly or in small clumps ( < 5) tended to have short, sometimes bulbous stipes with larger pilei, while those in larger clumps had elongate stipes of paler colour and smaller pilei. The latter was seen most frequently, solitary and subcaespitose habits being more the exception. In the production of large clumps of basidiomes, A. luteobubalina resembled A. mellea s.str. Dry weather following initiation could result in basidiomes with short thickened stipes and smalldiameter, umbonate and thick fleshed pilei, often dark-olivaceous in colour. Exposure of freshly expanded basidiomes to sunny weather could result in them assuming a sandy olive-bleached appearance. Consistently moist conditions resulted in basidiomes with stronger yellow colours. MICRO-FEATURES

Basidia possessing transverse septa have been located intermixed with cheilocystidia, and in collection 102 from Victoria, and to a lesser extent in coll. 105 the sterigmata were irregularly elongated. Hartig (1874) illustrated similar abnormalities in Agaricus melleus and attributed them to the continued growth of the sterigmata when basidiomes were incubated under moist conditions. Parallel observations have been made in collections of several European species of Armillaria and are often associated with the production of thickened basidial walls. In some basidiomes of Armillaria bulbosa the entire basidium becomes thickened and often coloured, and is then termed a sclerobasidium. The function of these modified basidia is as yet unknown, but they do not occur in all species of Armillaria, and are absent in A. luteobubalina. Caulocystidia are always present especially at the stipe apex and may even give the stipe surface a powdery appearance, They are generally prominent in areas above the ring but elsewhere are intermixed with velar remnants. The width of lateral and mediostrata of the

Table

1.

79

hymenophoral trama and intensity of gelatinization of the lateral elements appears to vary and more critical observation is required. By using SEM techniques the basidiospores of A. luteobubalina are confirmed to be smooth (Fig. 6) in agreement with light microscope studies. This contrasts dramatically with the spores of A. mellea which have longitudinal ridges (Pegler & Young, 1970; Singer, 1975). The spore wall of A. luteobubalina consists of an electron-transparent outer layer, a fibrillar middle layer of uniform thickness and an irregularly thickened inner layer containing vesicular bodies (Fig. 7). The irregular thickening of the inner layers does not affect the spore surface, Flattening and folding of spore-walls observed in ultra-thin sections appeared to be artifacts, resulting from preparation or the compression of adjacent spores in the original spore-print. Spores collected on paper retained their original shape better during long-term storage than those collected on glass. The spore size determined for a number of collections made in Tasmania in 1974 was consistently larger than that of the holotype (coll. 6, Dumbrell Block 1974). Spore size was determined from 39 spore-prints, each from a single basidiome of 10, 4, 4 and 21 collections from the four geographical regions of Tasmania, eastern Victoria, Australian Capital Territory (ACT) and westcentral Victoria respectively, Size was also determined from two spore-prints and eleven additional spore-prints in collections 6 and 206 respectively and nine spore-prints for each of collections 202 and 203, in order to examine variation in spore size between basidiomes of the same clump. The spores were mounted in 10 % ammonium hydroxide, and 25 from each print were measured, Coulter counter measurements (Kile, unpubl.) established that spore size is normally distributed in this species. For all 70 spore lots measured, the mean length ranged from 6'0 to 9'2 flm and mean width from 4'2 to 5'8 flm (Fig. 8). The upper and lower limits of the range for length were established by collections 116 from west-central Victoria and 65 from Tasmania and for width by collections 202 from west-central Victoria and collection 126 from the

Mean basidiospore size (flm) for collections of A. luteobubalina from west-central Victoria, eastern Victoria, Tasmania and the Australian Capital Territory

West-central Victoria Eastern Victoria Tasmania Australian Capital Territory

Observations

Length (S.E.)

Width (S,E.)

Ratio (S.E.)

21 4

7'29 (0'126) 7"30 (0'4 23) 7'71 (0'254) 7.88 (0'4 07)

4'95 (0'049) 4'99 (0'13 0) 4'94 (0'074) 5'21 (0'245)

1'48 1'47 1'57 1'57

10

4

(0'021) (0'049) (0'04 1) (0'075)

80

Armillaria luteobubalina

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'" Victoria - Eastern .. Victoria ~ Eastern (Holotype) o Victoria - West-Central • Victoria - West-Central (Collection 202) • Victoria - West-Central (Collection 203) • Victoria - West-Central (Collection 206) c Australian Capital Territory

•

4·0

6·0

6·5

+

0

+

7·0

7·5

8·0

8·5

9·0

Spore length (JIm)

Fig. 8. Basidiospore sizes of A. luteobubalina determined from 70 spore-prints from basidiomes collected in Tasmania, eastern Victoria, west-central Victoria and the Australian Capital Territory (each point represents the mean of 25 spores). ACT (Fig. 8). Q values (length:breadth ratio) were calculated at 1'27-1'74, covering forms from broadly ellipsoid to elongate (Bas, 1969). The spore size of the holotype was at the lower end of the range for length and approximately mid-range for width (Fig. 8). Differences in mean length ( < 1 lim) and width « 0' 5 lim) between spores from different basidiomes of the same clump were approximately one-third of the overall range for those parameters across all collections (Fig. 8). When the spore size was analysed on the basis of the four geographical regions using a one-way analysis of variance with the mean figures for each of the replicated collections, no significant difference (P < 0'05) in spore length, width or ratio (Table 1) was detected between the areas. To detect a difference significant at the 5 % level between means whose true values for length differ by 0'4 pm (the difference observed between westcentral Victorian and Tasmanian means for length) at least 20 spore-prints from different collections in each area would need to be measured.

The relatively small range of spore size within the collections and the lack of any systematic pattern of variation on a regional or local basis is compatible with a single species concept for the material examined. Variation is presumably accounted for by genotypic and other factors such as the age of the basidiome and environmental conditions or substratum, known to influence basidiospore size (Smith, 1977; Watling, 1977). BASIDIOME PRODUCTION IN VITRO

Basidiomes of A. luteobubalina were grown III 500 ml Erlenmeyer flasks on 70 g Zea mays L. kernels just submerged in 2 % malt extract solution (Swift, pers. comm.). After autoclaving, flasks were inoculated and incubated in the dark at 25°C for 3-6 weeks to allow vegetative growth to take place. Flasks were then either incubated in a growth chamber under white fluorescent light (12 h day, 12 h night) at 25° or placed in diffuse natural light in an unheated or partially heated room. Three isolates, K 25 and K 107 from eastern

G. A. Kile and R. Watling Tasmania and the type isolate K 74 (ATCC 38574), were tested. Basidiomes were initiated and developed by the three isolates, although only in the flasks incubated in diffuse daylight. Mature basidiomes were produced over a much longer period (Mar.-Aug.) than the field basidiome season. After the initial incubation period which favoured vegetative growth, the ability to initiate basidiomes was independent of the age of the culture. These results suggest that the seasonal or diurnal temperature regime or the spectral composition of the light, or both, are critical factors in initiation and development of the basidiomes of A. luteobubalina. Basidiomes produced in culture were generally paler and possessed thicker stipes than those found in the field, but they were readily recognizable as A. luteobubalina. Other characteristics such as hymenophoral trama and pileipellis structure, the taste of both flesh and pileus cortex, spore-size and colour were normal. The spores produced in vitro by ATCC 38574 measured 6'5 x 5'0 [lm compared with the mean of 6'7 x 4'8 [lm determined from 3 spore-prints of the holotype. BIOLUMINESCENCE

Although bioluminescence can be demonstrated in several species of Armillaria it is considered an unreliable character. It varies even within isolates of the same species, both in vivo and in vitro. Sapwood of Eucalyptus spp. decayed by A. luteobubalina exhibits weak to strong luminescence; the latter as in A. mellea and A. bulbosa is normally associated with the most vigorously growing mycelium. The presence of bioluminescence in A. luteobubalina is at variance with the earlier report by Podger et al. (1978) in which Eucalyptus regnans sapwood decayed by the present species was non-luminescent. Cultures on 3 % malt extract agar are normally non-luminescent or only weakly so, but most isolates are luminescent to some degree when grown on 10 % bread agar (Berliner, 1961). Such variation is now expected as normal for a species. HOSTS

Most of the recorded hosts of A. luteobubalina are members of Myrtaceae or Mimosaceae but records in other families, including Liliaceae and Cyperaceae (Monocotyledoneae), confirm that the species has a broad host range. To qualify as a host the following two criteria were used; either basidiomes were collected from the infected plant or isolates of characteristic morphology (Podger et al., 1978), were made from living or recently

81

dead tissue, at locations where basidiomes had been previously collected. Australian native species. Acacia dealbata Link, A. howittii F. Muell., A. mearnsii De Wild., A. melanoxylon R.Br., A. mucronata Willd. ex H. Wendl., A. verticillata (L'Herit.) Willd., Cassinia aculeata (Labill.) R.Br., Daviesia ulicifolia Andr., Dianella sp., Eucalyptus baxteri (Benth.) Maid. & Blakely, E. camaldulensis Dehnh., E. dives Schau., E. globulus (Labill.) ssp. bicostata (Maid. et al.) Kirkp., E. macrorhyncha F. Muell. ex Benth., E. melliodora A. Cunn. ex Schau., E. obliqua L'Herit., E. ovata Labill., E. radiata Sieb. ex DC., E. regnans F. Muell., E. tubida Deane & Maid., E. viminalis Labill., Gahnia psittacorum Labill., Grevillea rosmarinifolia A. Cunn., Hibbertia obtusifolia DC., Melaleuca decustata R.Br., M. ericifolia Sm., Olearia argophylla (Labill.) Benth. Introduced species. Chamaecytisus proliferus (L.f.) Link, Malus sylvestris (L.) Mill., Pinus radiata D.Don. Specimens examined. Tasmania - 2, 8412-75°443, 21 May 1974,G.A.K. (E, DAR 34953); 3, 8412-739441, 21 May 1974,G.A.K. (E, DAR 34954); 4, 8414-774925, 22 May 1974, G.A.K. (E, DAR 34955); 5, 8514-067874, 22 May 1974, G.A.K. (E, DAR 34956); 15, 8412739441, 22 May 1975, G.A.K. (DAR 34958); 65, 8412-750442,27 Apr. 1976, C. Turnbull (DAR 34959); 67,8412-750442,27 Apr. 1976, C. Turnbull (E, DAR 34960); 71, 8412-739441, 12 May 1976, C. Turnbull (DAR 34961); 211, 8313-357957, 23 June 1978, F. Podger; 330, 7816-230812, 22 May 1979, G.A.K. (E, DAR 34983); 334, 7816-227812, 22 May 1979, G.A.K. (DAR 34984); 335,22 May 1979,7816-226812, G.A.K. (E, DAR 34985). Victoria - 6, 8221-577495, 30 May 1974, G.A.K. (holotype) (E, DAR 34957); 31, 8221-577495, 2 june 1975, G.A.K. (E); 101, 7523-9897°5, 25 May 1976, G.A.K. (DAR 34962); 102, 7523-008667, 25 May 1976, G.A.K. (E, DAR 34963); 103, 7523-009668, 25 May 1976, G.A.K. (DAR 34964); 1°4,7523-9787°9, 25 May 1976, G.A.K. (DAR 34965); 1°5,7523-017665, 25 May 1976, G.A.K. (E, VPRI 10958); 106, 7523974728,24 May 1976, G.A.K. (E, VPRI 10959); 107, 7523-009678, 26 May 1976, G.A.K. (VPRI 10960); 108, 7523-996702, 27 May 1976, G.A.K. (VPRI 10961); 109, 7523-008698, 30 May 1976, G.A.K. (E, VPRI 10962); 110,7523-975730,30 May 1976, G.A.K. (E, VPRI 1°963); 111, 7623-473575, 29 May 1976, G.A.K. (DAR 34966); 112, 5J 55-5-240386, 5 June 1976, G.A.K. (DAR 34967); 113, 5J55-5-243384, 16 June 1976, G.A.K. (E, DAR 34968); 114, 75239957°4,18 June 1976, G.A.K. (E, DAR 34969); 115, 7523-997703, 18 June 1976, G.A.K. (E, DAR 34970); 116, 7523-012697, 18 June 1976, G.A.K. (VPRI 1°964); 117, 5J55-5-225374, 19 June 1976, G.A.K. (VPRI 10965); 118, 7523-011668, 22 June 1976, G.A.K. (E, VPRI 10966); 119,7523-014696,22 June 1976, G.A.K. (E, VPRI 1°967); 120, SJ55-5-230389,

82

Armillaria luteobubalina

15 July 1976, G.A.K. (VPRI 10968); 121, SJ55-5265390, 29 May 1977, J. Kellas (VPRI 1(969); 122, SJ55-5-245384, 29 May 1977, J. Kellas (E, VPRI 10970); 123, SJ55-5-267392, 29 May 1977, J. Kellas (VPRI 1(971); 200, SJ55-5-265391, 19 Apr. 1978, G.A.K. (DAR 34972); 201,7623-573475,13 May 1978, G.A.K. (E, DAR 34973); 202, 7523-998702, 22 May 1978, G.A.K. (E, DAR 34574); 203, 7523-977708, 22 May 1978, G.A.K. (E, DAR 34975); 204, 7523995706, 22 May 1978, G.A.K. (DAR 34976); 205, 723-017665,22 May 1978, G.A.K. (DAR 34976); 205, 7523-017665, 22 May 1978, G.A.K. (DAR 34977); 206, SJ55-5-214378, 23 May 1978, G.A.K. (E, DAR 34978); 207, SJ55-5-213378, 24 May 1978, G.A.K . (VPRI 10972); 208, SJ-55-5-215378, 24 May 1978, G.A.K. (E, VPRI 10973); 209, SJ-55-5-218379, 24 May 1978, G.A.K. (E, VPRI 10974); 210, SJ-55-5218393, 28 May 1978, G.A.K. (VPRI 10975); 301, 7523-971733,26 Apr. 1979, G.A.K. (E, VPRI 10976); 302, SJ-55-5-234384, 29 Apr. 1979, G.A.K. (E, VPRI 10977); 303, SJ-55-5-214378, 29 Apr. 1979, G.A.K . (E, VPRI 10978); 305, 7523-977730, 1 May 1979, G.A.K. (VPRI 10979); 306, 7523-976733, 1 May 1979, J. Owen (VPRI 10980); 307, 7523-975734,1 May 1979, J. Owen (VPRI 10981 ); 308, 7523-971730,1 May 1979, J. Owen (VPRI 10982); 309, SJ-55-5-213378, 6 May 1979, G.A.K. (E, VPRI 1°983); 310, SJ-55-5-213377, 6 May 1979, G.A.K . (E, VPRI 1°984); 316, 7523995705, 17 May 1979, G.A.K. (VPRI 10985); 317, 7523-975731, 17 May 1979, G.A.K. (E, VPRI 10986); 318, 7523-975732, 17 May 1979, G.A.K. (VPRI 10987); 319, 7523-975728, 17 May 1979, G.A.K. (VPRI 10988); 320, 7523-975731, 17 May 1979, G.A.K. (VPRI 1°989); 321, 7523-976729, 17 May 1979, G.A.K. (VPRI 10990); 322, 7523-974731, 17 May 1979, G.A.K. (VPRI 10991); 323, 7523-981729, 17 May 1979, G.A.K. (VPRI 10992); 324, 8522922153, 5 June 1979, G.A.K. (DAR 34979); 325, 8522-161197, 5 June 1979, G.A.K. (E, DAR 34980) ; 326,8722-056320, 17 May 1979,P. Fagg (DAR 34981) ; 327, 8522-192186, 5 June 1979, G.A.K. (E, DAR 34982); 339, SJ-55-5-3 13328, 10 June 1979, 1. Smith (VPRI 10993); 341, 7523-974729, 2 July 1979, J. Owen (DAR 34988); 342, SJ-55-3-532539 (approx.), May 1978, M. Cole (E). Australian Capital Territory - 126, 8626-749-765, 25 May 1976, G.A.K. (E, DAR 34971); 338, 8626-737676, 6 May 1979, K. Old (DAR 34986); 340 (a) (b), 8626-713-745, 14 May 1979, K. Old (E, DAR 34987). Map references given where possible on 1: 100000 scale map sheets. The prefix SJ indicates 1: 250000 scale map sheets.

(K ile, unpubl.) by the yellow-olive ground colour of the pileus, the characteristic annulus, the easily peeling pileipellis and the astringent taste of the pileipellis and flesh. While the species has undoubtedly been recorded previously, in most cases it has probably been misidentified as A . mellea. As a recent example, it has been possible through the courtesy of the authors to confirm that the plate in Cole et al. (1978) figured as A. mellea is in fact A . luteobubalina. Environmental in addition to genetic factors are undoubtedly significant in the variation observed in A. luteobubalina. This species may prove to be a macrospecies consisting of several inter-sterile populations (microspecies) which are not differentiated by prominent morphological criteria as demonstrated in other groups of agarics (Watling, 1977). Although very minor morphological differences might be found between collections, generally when enough collections are examined the one collection merges into another. Inter-sterility amongst populations distributed across a wide geographic area might be expected, particularly in the case of the Tasmanian populations, which, in the absence of long-distance spore dispersal, could have been separated from mainland populations from 1300 years B.C. when the land bridge between Tasmania and mainland Australia became submerged (Jennings, 1971). Armillaria luteobubalina is a primary pathogen of Eucalyptus spp. in fore sts in the western highlands of Victoria (Kile, 1981) and of E. regnans in a plantation in eastern Victoria (Podger et al., 1978). It is also associated with gully dieback of E. obliqua in north-eastern Tasmania (Palzer, 1980) and some of the mortality of amenity and ornamental trees and shrubs in parks and gardens in the eastern suburbs of Melbourne. The authors gratefully acknowledge the assistance of P . Fagg, J. Kellas, K. M. Old, J. Owen, F . D . Podger, I. M. Smith and C. R . A. Turnbull for collecting basidiomes, K. M. Old for the electron micrographs of basidiospores and B. Aeberli, R . G. Jarrett, V. Lord and R. L. Tweedie for assistance with the statistical analysis of spore measurements. We also thank Dr M. J. Swift for the initial information on the production of basidiomes in vitro.

CONCLUSIONS

Armillaria luteobubalina is widely distributed in south-eastern Australia although the northern and western limits to its distribution have yet to be defined. Its wide distribution in endemic plant communities suggests that it is a native species . The species is readily distinguished from other Armillaria species found in south-eastern Australia

REFERENCES

BAS, C. (1969). Morphology and subdivision of Amanita and a monograph on its section Lepidella. Persoonia 5, 285-579. BERLINER, M. D. (1961). Studies in fungal luminescence. Mycologia 53, 84-90.

G. A. Kile and R. Watling COLE, M. F., FUHRER, B. & HOLLAND, A. (1978). A Field Guide to the Common Genera of Gilled Fungi in Australia. Melbourne : Inkata Press . HARTIG, R. (1874). lVichtige Krankheiten der lValdbaume. Berlin : J. Springer. English translation by W. Merrill, D . H. Lambert and W. Liese. Published by American Phytopathological Society 1974. Pp.120. JENNINGS, J. N. (1971). Sea level changes and land links. In Aboriginal Man and En vironment in Australia (ed. D. J. Mulvaney & J. Golson). Canberra: ANU Press. KILE, G. A. (1981). Armillaria lute obubalina : a primary cause of decline and death of tree s in mixed species eucalypt forests in central Victoria. Australian Forest Re search (In press ). PALZER, C. (1980). The etiology of gully dieback . In Eucalypt Dieback in Forests and 1V00diands (ed. K. M. Old, G. A. Kile & C. P. Omart). Conference Proceedings, C.S.I.R.O. Melbourne.

PEGLER, D. N. & YOUNG, T. W. K . (1970). Basidiospore morphology in the Agaricales, Beihefte von No va Hedwigia 35, 1-210. PODGER, F. D., KILE, G. A., WATLING, R. & FRYER,]. (1978). Spread and effects of Armillaria luteobubalina sp.nov. in an Australian Eucalyptus regnans plantation. Transactions of the British Mycological Society 71, 77-87. SINGER, R. (1975). The Agaricales in Modern Taxonomy. 3rd ed . Vaduz: J. Cramer. Pp. 912. SMITH, A. H. (1977). Speciation in Lactarius. In The Spe cies Concept in Hymenomycetes (ed. H . Clemencon). Herbette Symposium, University of Lausanne, Switzerland, August 1976. Vaduz : ] . Cramer. WATLING, R. (1977). An analysis of the taxonomic characters used in defining the species of the Bolbitiaceae. In The Species Concept in Hymenomycetes (ed. H. Clemencon), Herbette Symposium, University of Lausanne, Switzerland, August 1976. Vaduz : J. Cramer.

(Received for publication 9 September 1980)