Tremellodendron is a genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 of fungi in the family Sebacinaceae. Its species are mycorrhizal, forming a range of associations with trees and other plants. Basidiocarps (fruit bodies) are produced on soil and litter

Plant litter

Plant litter, leaf litter or tree litter is dead plant material, such as leaves, bark, needles, and twigs, that has fallen to the ground. Litter provides habitat for small animals, fungi, and plants, and the material may be used to construct nests. As litter decomposes, nutrients are released to...

. The fruit bodies are clavarioid

Clavarioid fungi

The clavarioid fungi are a group of fungi in the Basidiomycota typically having erect, simple or branched basidiocarps that are formed on the ground, on decaying vegetation, or on dead wood. They are colloquially called club fungi and coral fungi...

 (club or coral-shaped) and leathery to rubbery-gelatinous. The genus is restricted to the Americas.

History

The genus was first published in 1902 by American mycologist George Francis Atkinson who had discovered that two species of branched, coral-like fungi previously referred to Thelephora

Thelephora

Thelephora is a genus of fungi within the Thelephoraceae family. The genus has a widespread distribution and contains about 50 species. Fruit bodies of species are leathery, usually brownish at maturity, and range in shape from coral-like tufts to having distinct caps...

(Tremellodendron candidum and T. schweinitzii) possessed septate

Septum

In anatomy, a septum is a wall, dividing a cavity or structure into smaller ones.-In human anatomy:...

 basidia, similar to those found in the genus Tremella

Tremella

Tremella is a genus of fungi in the family Tremellaceae. All Tremella species are parasites of other fungi and most produce anamorphic yeast states. Basidiocarps , when produced, are gelatinous and are colloquially classed among the "jelly fungi". Over 100 species of Tremella are currently...

. He therefore established Tremellodendron to accommodate branched, Thelephora-like fungi with "tremelloid" basidia. A few additional species were described by subsequent authors. Edward Angus Burt, who monograph

Monograph

A monograph is a work of writing upon a single subject, usually by a single author.It is often a scholarly essay or learned treatise, and may be released in the manner of a book or journal article. It is by definition a single document that forms a complete text in itself...

ed the genus in 1915, placed Tremellodendron within the Tremellaceae

Tremellaceae

The Tremellaceae are a family of fungi in the order Tremellales. The family is cosmopolitan and contains both teleomorphic and anamorphic genera, most of the latter being yeasts. All teleomorphic species of fungi in the Tremellaceae are parasites of other fungi, though the yeast states are...

. It remained in this family until 1992, when it was transferred to the newly established Sebacinaceae.

Current status

Molecular research, based on cladistic analysis of DNA sequences, has supported the placement of Tremellodendron within the Sebacinaceae. It has, however, also shown that the genus is polyphyletic and may not be distinct from the genus Sebacina

Sebacina

Sebacina is a genus of fungi in the family Sebacinaceae. Its species are mycorrhizal, forming a range of associations with trees, orchids, and other plants. Basidiocarps are produced on soil and litter, sometimes partly encrusting stems of living plants. The fruit bodies are cartilaginous to...

.

Description

Fruit bodies are typically densely branched, the branches erect and leathery to rubbery-gelatinous. In some species the branches tend to fuse together. Colours range from whitish or ochre to brown or reddish brown. Spores are white in mass. Microscopically, the fruit bodies are composed of hyphae lacking clamp connection

Clamp connection

A clamp connection is a structure formed by growing hyphal cells of certain fungi. It is created to ensure each septum, or segment of hypha separated by crossed walls, receives a set of differing nuclei, which are obtained through mating of hyphae of differing sexual types...

s in a gelatinous matrix. The spore

Spore

In biology, a spore is a reproductive structure that is adapted for dispersal and surviving for extended periods of time in unfavorable conditions. Spores form part of the life cycles of many bacteria, plants, algae, fungi and some protozoa. According to scientist Dr...

-bearing surface is initially covered in a layer of weakly branched hyphidia below which the basidia are formed. The basidia are tremelloid (ellipsoid and vertically septate), giving rise to long, sinuous sterigmata

Basidium

thumb|right|500px|Schematic showing a basidiomycete mushroom, gill structure, and spore-bearing basidia on the gill margins.A basidium is a microscopic, spore-producing structure found on the hymenophore of fruiting bodies of basidiomycete fungi. The presence of basidia is one of the main...

 or epibasidia on which the basidiospores are produced. These spores are ellipsoid to oblong, smooth, and colourless.

Habitat and distribution

Tremellodendron species were assumed to be saprotrophic until DNA analysis of mycorrhizal roots

Mycorrhiza

A mycorrhiza is a symbiotic association between a fungus and the roots of a vascular plant....

 showed that they were plant associates. They are now known to be ectomycorrhizal associates of forest trees. Species are confined to eastern North America, Central America, the Caribbean islands, and South America.