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Page number:13 
Description type:Non-original description 
Description:Clavulinopsis subtilis (Pers. per Fries) Corner, Ann. Bot. Mem. 1: 391. 1950. PL 2 A; Figs 12-17. Clavaria subtilis [Persoon] Fries, Systema Mycologicum 1: 475. 1821. =Clavaria dichotomy Godey. in Gillet, Les Champignons qui croissent en France 1, p. 766. 1878.
Clavulinopsis dichotoma (God.) Corner, Ann. Bot. Mem. 1: 365. 1950.
ILLUSTRATIONS: Bresadola (1932a, tab 1096).
Fruiting bodies 0.5-4 cm high, branched, stem portion 1-10 mm thick, white, villose-hispid or tomentose, longitudinally ridged and channelled, often lacunose or made up of several smaller fused individuals; branching generally dichotomous, axils lunate to open-acute; cream to pale yellowish cream when young to dull ochraceous cream in age; branch apices rounded to acute, usually slightly darker than branches. Hymenium gray-green in FeSO4, darkening in FeSO4 + ETOH. No reactions in G + H2O, G + ETOH, or KOH. Scattered to gregarious on leaf litter or (rarely) rotting wood.
Contextual hyphae up to 13 µm diam, generally parallel, but with some branching and anastomoses; clamp connections numerous, but not invariable; not inflated, hyaline in the medullary portion, often pale yellow toward the subhymenial area; often with slightly thickened walls, especially toward the fruiting body base. Subhymenial hyphae up to 4 µm diam, thin-walled, tortuous (pseudoparenchymatous in some specimens), clamped, producing basidia in clusters; usually with pale yellowish vacuoles or guttules. Hymenium thickening; basidia short, 25-45 x 3.6-5.5 µm, clamped, pigmented with pale yellowish guttulae in the cytoplasm, 4-sterigmate; sterile hymenial elements paraphysoid, undifferentiated, narrow, straight hyphae, protruding 5-20 µm from the young hymenium (Figs 14, 15).
Spores 4.2-6.3 x 3.0-4.5(-5.6) µm, subglobose to ovate, smooth, thin-walled, uniguttulate, with a prominent, conical apiculus 0.5-1.5 µm long (Fig 17).
The inclusion of this species opens the whole issue of the small-spored species of Clavulinopsis. Several of these species, such as C. similis Corner, C. michelii (Rea) Corner and C. depokensis (v. Ov.) Corner have been included in Clavulinopsis by Corner (1950), who also conjectured about their evolution. C. biformis, C. rufipes, C. luteo-ochracea and C. minutula have been removed from Clavulinopsis to Ramariopsis (Petersen, 1964, 1966), others have been included in a generally phycophilous group (Petersen, 1967a) (C. constans, C. pogonati, C. vernalis, etc. see discussion under "Excluded species"), and some others may have to be transferred when type material is studied carefully. At any rate, the complex of small-spored Clavulinopsis-like species is undergoing revision. In part, the complex may have close ties with the rest of Clavulinopsis, or may have arisen as a smooth-spored offshoot from Ramariopsis, or both. Certainly the hysterochroic C. fruticula is very close to Ramariopsis, but there is apparently no type specimen available to validate Corner's description.
The distinction between C. subtilis and C. minutula is clear, although these and other species have been greatly confused in the past. TABLE IV lists spore dimensions and basidial lengths for the two species, on which bases they can be separated. Corner (1950 and annotated specimens at CGE and BPI) did not draw proper distinctions between them. His specimens under C. biformis at CGE are smooth-spored, but the type of this species bears rough spores and so belongs in Ramariopsis (Petersen, 1964). A specimen at BPI under C. asperula Atk. was identified by Corner as C. minutula, but bears rough spores, making Corner's identification or his disposition of the species incorrect.
Within the past several years, I have become convinced that several small-spored "Clavulinopsis" species really have their affinities with Ramariopsis, as a smooth-spored subgenus. In this group I include C. minutula, the problematic C. fruticula, and two undescribed species from the eastern U.S.A. The only smallspored species of Clavulinopsis which I accept for North America is C. subtilis, based on its characteristic spore form, and on its generally typical basidial morphology. Doubtless other species exist, but European type material and fresh specimens must be thoroughly studied before these species can be adequately and accurately described.
Specimens examined: as Clavaria subtilis: MICH: Kauffman (Mich.); KRS-5011 (Nova Scotia); CGE-Corner (England-2); RHP-1409 (Tenn.).
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