 Description： |
Basidiocarps gelatinous, foliose, hollow, often large, frondose when young, cornute when mature, up to 4 cm ø, 3 cm in height, yellow or sometimes whitish yellow, pure yellow or yellowish orange when mature, luteous when old; dry becoming yellow; sometimes white basidiocarps growing near yellow ones on the same stem; associated with Hypoxylon sp. Basidia mostly subglobose to oval, rarely pyriform, 14-16(-17) × 11-13 μm [Q=(1.08-)1.15-1.27 (-1.55)] (measurements not including stalks); longitudinally or obliquely cruciate-septate, 2- or 4-spored; stalks short, mostly 2-3 μm; sterigmata up to 70 μm in length, 2-3 μm ø, apically swollen up to 4-5 μm ø. Spores subglobose to ellipsoid, (6-)7-9(-13) × 5-6.5 μm [Q=(1.09-)1.17-1.33 (-2.36)], hyaline, smooth, germinating by budding, repetition or sometimes by germ tubes. Conidia absent. Vesicles absent. Swollen cells in the subhymenium and inner part of basidiocarps, mostly subglobose to oval, occasionally clavate, 6-17(-20) × 5-7 μm, thin- to thick-walled, smooth, hyaline. Hyphidia absent. Hyphae smooth, hyaline, 2-4 μm ø, in the inner part of basidiocarps sometimes up to 6 μm ø, thin- to thick-walled, gelatinous. Haustoria clamped, abundant and frequently branched, particularly close to the substrate. |
| Specimens： |
Taiwan, Hsinchu county, Kuanwu Forest, leg. C.-J. Chen, CCJ 907 on ascocarps of Hypoxylon sp. on decayed stems of Castanea carlesii (Hemsl.) Hayata var. sessilis Nakai.; Taiwan, Hsinchu county, Kuanwu Forest, leg. C.-J. Chen, CCJ 909; Taiwan, Hsinchu county, Kuanwu Forest, leg. C.-J. Chen, CCJ 928 (basidiocarps white mixed yellow) and CCJ 929 (basidiocarps pure yellow); Taiwan, Ilan county, Fusan Botanical Garden, leg. C.-J. Chen, CCJ 1022 & CCJ 1023; Taiwan, Hsinchu county, Kuanwu Forest, leg. C.-J. Chen, CCJ 1098; Taiwan, Taichung county, Tasheshan Forest, CCJ 1419 & 1420; Taiwan, Taichung, Tasheshan Forest, leg. W.-N. Chou, CWN 01469; Taiwan, Nantou county, Meifung, leg. Y.-Z. Wang, CWN 9221; Taiwan, Ilan county, Fushan Botanical Garden, leg. W.-N. Chou, CWN 00815; Taiwan, Hsinchu county, Yuanyanghu, leg. Y.-Z. Wang & S.-L. Shin, no. 93081012; Taiwan, Nantou county, Meifung, leg. Y.-Z. Wang, No. 92141. |
| Note： |
Such big and forked yellow basidiocarps were rarely reported. Macromorphologically, Tremella flava is very similar to T. sparassoidea Lloyd [syn. T. reticulata (Berk.) Farl. sensu Bandoni] published in 1920, which was described briefly without illustrations. Tremella sparassoidea grows from soil and has whit basidiocarps, while T. flava grows from bark of decayed wood associated with Hypoxylon sp. and has frequently pure yellow basidiocarps. They are two distinct taxa obviously. The hymenial structure of T. reticulata has also anastomoses frequently, but basidiocarps are ochraceous and have clampless hyphae (Bandoni, 1957). Tremella flava is also resembling T. iduensis Kobayasi (1939), but definitely differs in the size of basidia and basidiospores. Kobayasi did not mention whether his specimen was associated with Hypoxylon sp. in the description, but it is quite clear that T. iduensis is growing from such a host in his photograph (Kobayasi, 1939, Pl.II.B). Although the basidia and basidiospore measurements of T. flava and T. iduensis are distinct, apparently they are closely related.
Ecologically, the pure yellow T. flava basidiocarps are sometimes mixing with white, forked and hollow ones. They are of no difference microscopically but lacking yellow pigment in nature. The culture characters, however, are becoming the same, yellowish cream yeast form and yellowish primordial growing from yellow hyphae produced from yeast stage.
According to the similar hosts of Hypoxylon spp., Tremella flava is predictably related to T. fuciformis. Actually, molecular data indicated this species is grouped with T. fuciformis. This goes not only together with the similar hosts, but also with the hymenial structures.
Tremella cinnabarina (Mont.) Pat. is considered to resemble T. flava generally for the stout structure and cornute basidiocarps, but differs in hymenial structure and smaller basidiospores. Tremella samoensis Lloyd, synonymized to be T. cinnabarina by Bandoni (1957), and T. boninensis (Kobayasi) Ito & Imai, elevated from T. samoensis var. boninensis Kobayasi, seem comparable with T. cinnabarina in general. It is hard to say if they are the same taxon or not for the basidia and basidiospore measurements are not enough for delimitation.
A conspicuous difference between T. cinnabarina and T. flava is the hyphae of T. cinnabarina bearing basidia terminally then proliferating laterally from basidial clamps, while the probasidia of T. flava are frequently growing from the side of hyphae but not from basidial clamps. |
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Phylum：Basidiomycota >> Class： Basidiomycetes >> Order： Tremellales