Didymochlaena mesoamericana Li Bing Zhang & H.Shang
Descripción
Didymochlaena mesoamericana is most similar to D. amazonica and D. alpina in having oblong pinnules, but the former differs from the latter in linear scales at petiole base (vs. lanceolate scales).
Plants large, evergreen. Rhizomes erect. Fronds tufted, 1–2 m long. Petioles 30–50 cm, ca. 0.8–1 cm in diam at base; petiole base densely covered with linear black or brown scales up to 2 cm long. Laminae imparipinnate, oblong or elliptic, 70–150 × 40–50 cm, widest at middle, lower 1 or 2 pairs slightly contracted and forming 90–100-degree angle with petiole, apex acute. Rachises ca. 2–4 mm in diam at middle. Pinnae in 25–35 pairs, lanceolate, pinnae alternate, largest pinnae 20–25 × 3–3.5 cm, located at middle of laminae, very slightly contracted toward lamina base, basalmost pairs 75–80% as large as largest ones; two pairs 4.5–5 cm apart, middle pairs 2.5–3 cm apart; nearly sessile, apex acuminate; a pair of pinnules located at the pinna base with the upper ones overlapping rachis obviously. Pinnules in 15–25 pairs, dimidiate, nearly oblong, nearly sessile, chartaceous, base truncate, apex nearly round; basal pinnules subopposite, alternate upwards; largest pinnules located at middle part of pinnae, 1.5–1.7 × 0.6–0.9 cm, widest at base; lower 1–2 pairs contracted toward pinna base, basalmost lower pinnules 60–70% as large as largest ones, and basalmost upper pinnules changed to nearly circle, diam 0.6–0.8 cm; pairs 0.8–1 cm apart; proximal margins slightly overlapping costa, nearly entire; distal margins repand or crenate; basiscopic margins forming a 100–110-degree angle with costa, slightly curved and entire; acroscopic margins repand or crenate. Veins nearly visible abaxially but obscure adaxially, free, forked, hydathodous; midribs indistinct. Hydathodes borne on sterile veinlets, 0.3–0.5 mm from pinnule margins. Sori terminal on veinlets, 3–5 on acroscopic side, always 1–2 on basiscopic side, elliptic or linear, 2.5–3 × 0.5–0.8 mm, closer to pinna margins than to midrib, receptacles of sori 2.5–3 mm from pinnule margins, 5–6 mm from midrib, centers 2–3 mm apart from one another; indusia narrowly elliptic or linear, 2.5–3 × 0.5–0.8 mm, margins entire.
Etymology—The species epithet is referring to its distribution in Central America.
A
Plants large, evergreen. Rhizomes erect. Fronds tufted, 1–2 m long. Petioles 30–50 cm, ca. 0.8–1 cm in diam at base; petiole base densely covered with linear black or brown scales up to 2 cm long. Laminae imparipinnate, oblong or elliptic, 70–150 × 40–50 cm, widest at middle, lower 1 or 2 pairs slightly contracted and forming 90–100-degree angle with petiole, apex acute. Rachises ca. 2–4 mm in diam at middle. Pinnae in 25–35 pairs, lanceolate, pinnae alternate, largest pinnae 20–25 × 3–3.5 cm, located at middle of laminae, very slightly contracted toward lamina base, basalmost pairs 75–80% as large as largest ones; two pairs 4.5–5 cm apart, middle pairs 2.5–3 cm apart; nearly sessile, apex acuminate; a pair of pinnules located at the pinna base with the upper ones overlapping rachis obviously. Pinnules in 15–25 pairs, dimidiate, nearly oblong, nearly sessile, chartaceous, base truncate, apex nearly round; basal pinnules subopposite, alternate upwards; largest pinnules located at middle part of pinnae, 1.5–1.7 × 0.6–0.9 cm, widest at base; lower 1–2 pairs contracted toward pinna base, basalmost lower pinnules 60–70% as large as largest ones, and basalmost upper pinnules changed to nearly circle, diam 0.6–0.8 cm; pairs 0.8–1 cm apart; proximal margins slightly overlapping costa, nearly entire; distal margins repand or crenate; basiscopic margins forming a 100–110-degree angle with costa, slightly curved and entire; acroscopic margins repand or crenate. Veins nearly visible abaxially but obscure adaxially, free, forked, hydathodous; midribs indistinct. Hydathodes borne on sterile veinlets, 0.3–0.5 mm from pinnule margins. Sori terminal on veinlets, 3–5 on acroscopic side, always 1–2 on basiscopic side, elliptic or linear, 2.5–3 × 0.5–0.8 mm, closer to pinna margins than to midrib, receptacles of sori 2.5–3 mm from pinnule margins, 5–6 mm from midrib, centers 2–3 mm apart from one another; indusia narrowly elliptic or linear, 2.5–3 × 0.5–0.8 mm, margins entire.
Etymology—The species epithet is referring to its distribution in Central America.
A
Forma de vida
TerrestreA
Ejemplar revisado
Veracruz: San Andrés Tuxtla, 18°35′N 95°7′W, 480 m, 2 June 2006, T. Krömer & A. P. Peña 2747 (UC).A
Elevación
480 mA
Categoría IUCN
No incluidaB
Categoría NOM-059-SEMARNAT-2010
No incluidaC