page_title: Wynnea americana
section_title: Microscopic characteristics
hierarchical_section_title: Wynnea americana / Description / Microscopic characteristics
caption_attribution_description: English: Drawing of various microscopic features of the fungus Wynnea americana Thaxt. 1) Paraphyses; 2) An ascus showing connection with subhymenial filament; 3) Three spores, the upper in optical section; 4) Portion of a section of the subterranean sclerotium showing chambers and cortex; 5) Portion of walls between two chambers; 6) W. macrotis Berk. Three spores, two in optical section; 7) W. gigantea Berk. &amp; Curt. Three spores, one in optical section. Original screen capture had levels adjusted, and hand-drawn numbers replaced (and resequenced) with Photoshop by uploader.
context_page_description: Wynnea americana, commonly known as moose antlers or rabbit ears, is a species of fungus in the family Sarcoscyphaceae. This uncommon inedible species is recognizable by its spoon-shaped or rabbit-ear shaped fruit bodies that may reach up to 13 cm tall. It has dark brown and warty outer surfaces, while the fertile spore-bearing inner surface is orange to pinkish to reddish brown. The fruit bodies grow clustered together from large underground masses of compacted mycelia known as sclerotia. In eastern North America, where it is typically found growing in the soil underneath hardwood trees, it is found from New York to Michigan south to Mexico. The species has also been collected from Costa Rica, India, and Japan.
  Wynnea americana is distinguished from other species in the genus Wynnea by the pustules on the outer surface, and microscopically by the large asymmetrical longitudinally ribbed spores with a sharply pointed tip. The spores are made in structures called asci, which have thickened rings at one end that are capped by a hinged structure known as the operculum—a lid that is opened when spores are to be released from the ascus.
context_section_description: With many cup fungi, microscopic analysis of the anatomy and structure of the apothecium is necessary for accurate identification of species, or to help distinguish between related species that have a similar external appearance. In W. americana, the ectal excipulum (the outer layer of tissue comprising the apothecia) is 125 µm thick, and composed of dark angular to roughly spherical cells that are 40–70 µm in diameter. The angular cells form pyramidal warts on the outer surface. The medullary excipulum (the inner fleshy layer of tissue underneath the ectal excipulum) is almost gelatinous, composed of interwoven hyphae 10 µm in diameter.
  Several structural components are involved in spore discharge in W. americana, such as the ascus, the operculum, the suboperculum. The spore-bearing cells, the asci, are 330–400 µm long by 16–20 µm wide. The ascus has a thickened apical ring that is capped by a hinged operculum, a lid that is opened when spores are to be released from the ascus. The presence of the apical ring beneath the operculum and the slanted opening that results is a condition known as "suboperculate", and is shared with Cookeina tricholoma and Phillipsia domingensis, also in the family Sarcoscyphaceae.
  The spores are scaphoid (boat-shaped), and have dimensions of 35–38 by 12–14 µm. They are marked with prominent longitudinal grooves, and when mature, are apiculate (ending abruptly in a short point). The spores typically contain several oil droplets. The paraphyses (sterile cells interspersed among the asci) are 8–9 µm long and have internal partitions called septa. The structure of the septa has been investigated using transmission electron microscopy, which has revealed that W. americana has a single pore plugged by a "fan-shaped matrix"—an electron-dense region with a torus-shaped ring of translucent tissue wrapped around it. The pore plug resembles those found in the Sarcoscyphaceae species Sarcoscypha occidentalis and Phillipsia domingensis.
caption: Microscopic features of W. americana. Figures 3, 6 and 7 are the spores of: (3) W. americana, (6) W. macrotis and (7) W. gigantea.[1]
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