Basidiocarps foliose, the lobes caespitose, lobed or forked, or with margins incised or crenate or sometimes entire, crisped, undulate, firm-gelatinous, white, up to 5 cm ø and 3 cm high, dry becoming pale whitish yellow; lobes usually very thin, generally associated with Hypoxylon sp. Probasidia initials typically clavate, mostly proliferation from swollen and short hyphae, sometimes through the clamps of basidia; mature basidia predominantly subglobose to ellipsoid, some globose or narrow clavate, (9-)11-13(-17) × (7-)8-10(-11) μm [Q=(1.00-)1.20-1.86(-2.29)], longitudinally, obliquely or diagonally cruciate-septate, mostly 4-, occasionally 2- or 3-spored; sterigma up to 50 × 2 μm, apically swollen up to 4-5 μm. Spores broadly ellipsoid to ellipsoid, 7-8(-9) × (4-)5-6(-7) μm [Q=(1.14-)1.27-1.55(-1.70)], smooth, hyaline, germinating by budding, repetition or germ tubes. Conidia absent, but some clamped and catenulate cells looking like conidia, globose to broadly ellipsoid, mostly 8-11 × 6-10 μm [Q=1.0-1.23(-1.40)], abundant in basal parts close to the substrate, occasionally appearing in the hymenium on the surface of basidiocarps. Vesicles absent. Swollen cells in the inner part of basidiocarps, shape variable, mostly subglobose to oval, 9-14(-18) × 7-12(-15) μm [Q=(0.90-)1.12-1.43(-2.12)]; the terminally and subterminally swollen cells on the sterile surface in commercial basidiocarps existing close to the substrate, terminal cells subglobose to oval, occasionally pyriform with short stalks, (15-)35-52 × (15-)24-37 μm [Q=(1.00-)1.08-1.46(-1.73)] (measurements including stalks), stalks up to 4-6 μm long; subterminal cells, mostly citriform, tapering both sides, occasionally oval to capitate, 35-50 × 18-30 μm [Q=1.35-2.14(-1.78)] (measurements including stalks), stalks up to 17 μm long. Hyphidia absent. Hyphae in the inner part of basidiocarps mostly 2-4 μm ø, sometimes up to 6 μm ø; abundant ball-like hyphae close to clamps, frequently anastomosing with one to three neighboring cells, like a network; in the subhymenium mostly 4-7 μm ø, close to the substrate up to 12 μm ø; in the commercial material, hyphae in the hymenium and subhymenium variable in shape, mostly 7-20 ø. Haustoria abundantly in basal part close to the substrate, rarely in mature hymenium, clamped, haustorial hyphae branched often.
Specimens：
Taiwan, Taipei, Yangmingshan National Park, leg. C.-J. Chen, CCJ 1057, on Hypoxylon sp. growing on decayed stem of Prunus sp. (Sakura) and some decayed wood of Fagaceae.; Taiwan, Nantou, Huisun, leg. C.-J. Chen, CCJ 1072; Taiwan, Taipei, Yangmingshan National Park, leg. C.-J. Chen, CCJ 1090; China, Fujian Province, Shanming, Wuyishan, leg. C.-J. Chen, CCJ 1163 & CCJ 1164; Taiwan, Nantou county, Huisun Forest, CCJ 1241; Taiwan, commercial product, leg. C.-J. Chen, CCJ1531.
Habitat：
null
Distribution：
null
References：
Bandoni, RJ. 1957; Chen, CJ. 1998; Chen, PC and Hou, HH. 1979; Kobayasi, Y. 1939; Olive, LS. 1958.
Provided：
C. J. Chen
Note：
Tremella fuciformis is probably one of the most beautiful fungi growing in subtropical and tropical areas, or even temperate zone. It was first found in Brazil but is developed to artificially cultivated species in Taiwan, China and some other countries in Asia. It is clearly associated with Ascomycetes in the field, especially Hypoxylon spp., however, unlike other Tremella mycoparasites in basidiocarps of Basidiomycetes, the real host-relationship of this group is still not investigated.
The basidiocarps are firm. Even soaking in 5% KOH solution dose not release the hymenial structure. This is apparently due to the numerous anastomoses in the subhymenium. The similar structures can be seen from Tremella flava. Those fungi have three similarities: 1) the hyphae are frequently forming anastomoses, particularly in the subhymenium, 2) as soon as basidiospores were discharged, the basidium will collapse, 3) ecologically they are always associated with Hypoxylon sp. of Sphaeriaceae in nature.
Tremella fuciformis has two substantial characters in the inner part of basidicarps and subhymenium: 1) the hyphae are often swollen towards the clamps, and then forming predominately anastomoses with neighboring hyphae; 2) the numerous anastomoses, typically present in the subhymenium, make such basidiocarps very stout. The artificially cultivated basidiocarps are slightly different in structures. Particularly the very big swollen cells in chains are growing on the sterile surface of basal parts of basidiocarps close to the substrate. However, the variation is not great enough to be designated by a different name.
Olive (1958) reported from T. fuciformis collected in the area of Tahiti, that their basidiocarps are quite often parasites on a sphaeriaceous or phomaceous fungi. Nevertheless all the host-parasite relationships of them has not been clear until now. As an experience of cultivating T. fuciformis artificially, the culture is always mixed with mycelia of Hypoxylon sp. when inoculated into log or plastic bag. The real host-relationships should be investigated with TEM technique with host and parasite in pure culture interaction. Nevertheless, the interactions of haustorial and host hyphae can not be seen clearly in situ in the microscope. By checking the structures of hyphae in the substrate or between asci and Tremella hyphae, indeed no interaction can be observed. The definite character is haustoria hyphae on asci and in the substrate which are heavily branched.
Furthermore, Olive found that this species has vesicles in the hymenium. This could not be observed in my study. The Penicillium-like imperfect stage in the life cycle of T. fuciformis reported by Chen & Hou (1979) was probably only a contamination.
Kobayasi (1939) elevated a new genus, Nakaiomyces, which he found to resemble Tremella in every respect except for the presence of dark "setulae". It is obvious from his illustrations that the material he described was infected with imperfect fungi. Olive (1958) therefore believed Nakaiomyces is not a valid genus because some of his own collections from Tahitian had the same infection.
The structures of cultivated T. fuciformis CCJ 1531 are moderately different from typical basidiocarps in nature. For example, although the basidiocarps are well developed, the basidia are rarely mature, reversely most of them are remaining at young stage or becoming aborted cells. Therefore, basidiospores are hard to find. It is conceivable that such cultivated basidiocarps growing in a comfortable green house will lose the ability of their progenitor. Meanwhile, many swollen cells are found on the basal parts of basidiocarps close to the substrate, which cannot be found in nature.
Phylum：Basidiomycota >> Class： Basidiomycetes >> Order： Tremellales 
BCRC Number：