Tryonia
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Ordo: Polypodiales
Familia: Pteridaceae
Name
Tryonia Schuettp., J.Prado & A.T.Cochran gen. nov. – Wikispecies link – IPNI link – Pensoft Profile
Diagnosis
Similar to some species of Jamesonia, but with stramineous rather than castaneous rachises.
Type
Tryonia myriophylla (Sw.) Schuettp., J.Prado & A.T.Cochran, comb. nov., Gymnogramma myriophylla Sw., Kongl. Vetensk. Acad. Handl. 1817(1): 58. 1817.
Description
Plants terrestrial, rupicolous, or saxicolous. Rhizomes creeping to erect at apex, compact, with appressed hairs or crispate bristles, sometimes rigid, ruddy brown, darker at the base. Fronds erect, 6–100 cm long; petioles terete or sulcate adaxially, brown at base and stramineous distally, from 1/8 as long to equal the length of the lamina, densely to sparsely pubescent, the hairs short and erect or long and crispate, hyaline or reddish brown at the cell junctions, glandular or non-glandular; laminae linear to elongate-triangular, 1 or 2-pinnate-pinnatissect to 1–3-pinnate-pinnatifid, 4.0–48 cm long, 1.0–14 cm wide, determinate; rachises straight, sometimes slightly flexuous, terete or sulcate adaxially, stramineous, pubescent, the hairs like those of the petioles; pinnae ascending to patent to the rachis, oblong to deltate, 0.5–10 cm long, 0.5–5 cm wide, membranaceous to herbaceous, densely to sparsely pubescent on both surfaces, the hairs glandular, hyaline or with the terminal cell light to dark reddish brown, 2–5-celled, or hairs non-glandular, hyaline or reddish brown at the cell junctions, 2–5(–7)-celled; ultimate segments entire and round or emarginate; veins free. Sporangia borne along the veins, short-stalked, stalks 1–2-celled, stomia with 2–4 indurated cells; spores trilete, tetrahedral-globose, with an equatorial flange, distal face coarsely tuberculate, proximal face with prominent ridges, brown, 40–60 µm (Fig. 9).
Etymology
The generic name honors Dr. Alice Faber Tryon, who made extraordinary contributions to fern systematics and published taxonomic revisions of both Jamesonia sensu stricto and Eriosorus (from which Tryonia is segregated herein).
Distribution
Tryonia occurs primarily in southeastern Brazil. However, one species (Tryonia myriophylla) can also be found in Uruguay (Cerro Largo: Sierra Souza), near the Brazilian border. The genus is mostly restricted to the Atlantic Forest, along shaded streams, on damp shaded sandstone, or in more open places (but here shaded by shrubs); 600–2300 m.
Discussion
Tryonia can be distinguished most readily from Jamesonia by its stramineous rachises, but its gross morphology is also reasonably distinct. Tryon (1970)[1] referred to the leaves of Tryonia myriophylla as “generalized” (i.e., elongate-triangular and well developed). She drew a distinction between them and the “specialized” (i.e., either complex and scandent or compact and linear) leaves of Jamesonia sensu stricto and many other species at the time placed in Eriosorus, as well as between them and the “intermediate” (i.e., falling between the two extremes) leaves of other species she treated in Eriosorus. Although the Andean Jamesonia congesta also has “generalized” leaves, it is readily distinguished from Tryonia by its rachis color. The only species of Jamesonia with occasionally stramineous rachises (Jamesonia flexuosa) has “specialized” (complex and scandent) leaves. Spores of Tryonia (Fig. 9) and Jamesonia are basically indistinguishable.
Tryonia comprises the following species.
Original Description
- Cochran, A; Prado, J; Schuettpelz, E; 2014: Tryonia, a new taenitidoid fern genus segregated from Jamesonia and Eriosorus (Pteridaceae) PhytoKeys, 35: 23-43. doi
Other References
- ↑ Tryon A (1970) A monograph of the fern genus Eriosorus. Contributions from the Gray Herbarium of Harvard University 200: 54-174.
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