Search on : Taxa descriptions

 


   
Description type:Original description 
Description:Ramaria ambigua sp. nov. Fiche 2, pl. 6; Fig. 94.
Fruit bodies up to 12 x 3 cm, repeatedly branched, usually arbuscular, erect; stipe up to 21 x 4 mm, terete or lobed in cross section, pallid cream below, pale ochre above ("warm buff"), very locally strongly brunnescent on bruising, arising from a white mass of slender rhizomorphs and irregular mycelial pad. Major branches erect, several, terete, fleshy ochre ("ochraceous buff") to dull orange-ochre ("ochraceous tawny"); axils rounded; internodes diminishing gradually; upper branching dichotomous; hymenium amphigenous. Apices yellow ('buff-yellow"), awl shaped. When severed, upper branches quickly suffuse slate-olive about 0 S mm from cut; stipe surface
similar, but capricious; when crushed, branches slowly turn dark brown. Odour earthy; taste bitter. Under Dacrydium and tree ferns.
Macrochemical reactions: NOH = leaching coppery red; KOH=leaching dull ochre; PYR,ANO= positive; FCL =deep olive-green; PHN =negative.
Tramal hyphae of branches 2-4 µm diam., clamped, hyaline, adherent, parallel, tightly packed. Basidia 30-35 x 5-7 µm, subcylindrical, clamped, abruptly emergent from hymenium when mature, persistent after spore discharge; contents granular; sterigmata4, erect, spindly.
Spores (Fig. 94) 8.6 -11.2 x 3.6 - 4.7 µm (E = 2.08-2.80; Em = 2.51; Lm = 9.70 µm) elongate comma-shaped, with pronounced suprahilar depression, and often appearing inflated distally; contents uniguttulate to granular; wall up to 0.2 µm thick; hilar appendix appearing curved; ornamentation of very narrow, very sharp spines up to 2.2 µm long.
COMMENTARY: Macroscopically, fruit bodies of Ramaria ambigua strongly resemble slender individuals
of R. decurrens var. australis (Coker) Pet. (cf. Petersen 1982), with snow-white basal mycelium, ochraceous branches and yellow apices. Were fruit bodies of R. subdecurrens var. burnhami Pet. larger, and were they to show amphigenous hymenium, they too would be similar to those of R. ambigua. Bruising reactions seem similar to naturally occuring colours in R. decurrens var. australis. The geographic ranges of these taxa do not overlap that of R. ambigua, but the latter can be distinguished, nonetheless, by its bright ochre coloration and usuallyelongate shape of the fruit body.
Micromorphology resembles that of Ramaria subdecurrens (Coker) Corner. Spores of the latter are smaller (5.9 - 8.9 x 3.0-3.7 µm; E =1.78 - 2.25; Em = 2.06; Lm = 7.37 µm). Within section Flaccidae (Corner) Pet. (cf. Petersen 1981), spores longer than 9 µm are very unusual, and even more so with such high E values. All this convinces me that R. ambigua seems closest to R. subdecurrens, but is sufficiently distinct from other taxa to warrant a new species based on rather scanty material.
The species epithet signifies the ambiguous similarities of fruit body and micromorphology, as well as the ambiguous bruising reactions.
 
Taxon name: