Ramaria flavosaponaria

The specific epithet is from the flavo ('yellow')[3] and saponaria ('soapy'),[4] both of which are distinguishing features of the mushroom.[1] The name was originally published as Ramaria flavo-saponaria, including a hyphen.[1] However, this is considered erroneous by the International Code of Nomenclature for algae, fungi, and plants, so the proper orthography is Ramaria flavosaponaria.[5]

Before being formally described in 1986 by Ron Petersen, the species was labelled in scientific collections under various names.[1] Ramaria aurea sensu mihi was used for its resemblance to the European Ramaria aurea.[1] It was also sometimes labeled Ramaria aquafaba,[1] at least as early as 1969,[6] predating the 2015 coinage of the term aquafaba in an unrelated culinary usage.[7] This term possibly relates to the use of some yellow species of Ramaria (possibly including R. flavosaponaria) to make flavorful broth.[8] cooked R. flavosaponaria has a beany flavor,[1][2] so this 'bean water' (Latin aqua + faba[7]) likely led to the early R. aquafaba name.

Ramaria flavosaponaria is easily distinguished from related mushrooms by the brilliant gold color, the large number of aborted branchlets, a surface that feels slippery, a lack of clamp connections, and a complex spore ornamentation.[1] It is sometimes confused with Ramaria aurea, which only grows in Europe.[1] Ramaria stuntzii also lacks clamps, has small spores, and aborted branchlets, but is a bright red color and not slippery to the touch.[1] There is also a similar Ramaria species in Nova Scotia that is bronze-colored and also not slippery.[1] Macroscopically Ramaria primulina closely resembles R. flavosaponaria, but the former produces larger spores, has clamps, and flesh that is more gelatinous than soapy.[2]

Ramaria flavosaponaria has fruiting bodies up to 8 by 12 centimetres (3.1 in × 4.7 in) in size[2] that are broadly obovate to circular in shape and cespitose or scattered.[1] The irregularly shaped stipe grows up to 3 by 1.5 centimetres (1.18 in × 0.59 in) with much aborted branching, giving an appearance like cauliflower.[1][2] The flesh is white to yellow, does not bruise, but has a soapy texture without being gelatinous.[1][2] The above-ground parts are weakly vinescent (turning to a red wine color[9]) around particles of soil.[1][2] The flesh is brittle whether dried or fresh.[1]

The odor of fresh specimens is fabaceous (bean-like), which becomes like fenugreek upon drying.[1][2] The taste is described as moderately fabaceous,[1][2] but it is not known if the species is edible. A Colorado couple suffered gastrointestinal distress and cramps from a mushroom similar to the European R. aurea, but if this was R. flavosaponaria or another species is uncertain.[10]

The species tests positive with pyrogallol.[1][2] It is moderately positive in response to ferric chloride.[1][2] Tincture of guaiac is negative on the branch sections but weakly positive on the surface of the stipe.[1][2] Ammonium hydroxide and potassium hydroxide cause bleaching.[1][2] Testing with melzer's reagent is negative.[2]

The trama hyphae of the upper branches are no bigger than 7 μm in diameter and appear glassy, are hyaline, and lack clamp connections.[1][2] The areas near the septa are inflated up to 15 μm and are ornamented delicately.[1][2] Gloeoplerous hyphae are not present.[2][1] The hymenium is thickening, with clavate basidia that also lack clamp connections.[1][2]

The subcylindrical or narrowly ovate spores are 3.6-5.4 × 7.2-11.2 μm with roughened profiles.[1] The spores have walls up to 0.3 μm thick, with ornamentation of low warts and meandering, reticulate, and complex cyanophilous ridges.[1][2] Spore prints are cinnamon buff.[1][11]

R. flavosaponaria forms ectomycorrhizal relationships with Fagus sylvatica (European beech).[12] It has been found growing under Tsuga canadensis (eastern hemlock) and Quercus (oak) trees.[1][13]

• Media related to Ramaria flavosaponaria at Wikimedia Commons
• Data related to Ramaria flavosaponaria at Wikispecies