Glabrigrammitis Li Bing Zhang, X.M.Zhou, Jian Jun Yang & Parris, 2023

Yang, Jian-Jun, Parris, Barbara, Knapp, Ralf, Sundue, Michael, Zhang, Li-Bing & Zhou, Xin-Mao, 2023, Circumscription of the grammitid fern genus Oreogrammitis (Polypodiaceae) with the description of three new genera: Calligrammitis, Devolia, and Glabrigrammitis, Phytotaxa 597 (1), pp. 28-36 : 34

Glabrigrammitis Li Bing Zhang, X.M.Zhou, Jian Jun Yang & Parris , gen. nov.

Type: G. subevenosa (Baker) Li Bing Zhang, X.M.Zhou, Jian Jun Yang & Parris ≡ Polypodium subevenosum Baker, Syn. Fil. (Hooker & Baker) 320.186 7 ( Fig. 4 ).

Etymology —Latin glabri-, glabrous, and Grammitis , a genus of ferns, referring to the glabrous sporangia in comparison with the setose sporangia in the most similar genus, Oreogrammitis .

Diagnosis — Glabrigrammitis differs from other genera of Grammitidoideae by the following combination of characters: rhizomes dorsiventral, rhizome scales glabrous, concolorous, stipes absent or very short, fronds not articulated to rhizome, laminae simple, without sclerotic margin, setae present, branched hairs with setae as branches present, hairs pale, veins simple or 1-branched, vein endings with hydathodes present on adaxial surface of lamina, sometimes with a white deposit, sporangia glabrous.

Glabrigrammitis is similar to Oreogrammitis but differs in having glabrous, rather than setose sporangia. Glabrigrammitis is particularly similar to O. adspersa , but Glabrigrammitis has glabrous sporangia and always has a white deposit on the hydathodes, while the latter has setose sporangia and sometimes has a white deposit on the hydathodes ( Parris, 2013). Glabrigrammitis differs from nearly all species of Oreogrammitis in having branched hairs with setae as branches.

Description —Rhizomes short creeping. Stipes sometimes with hairs. Laminae linear to linear-oblanceolate, obtuse to acute at apex, margin entire or undulate. lateral veins visible or not transmitted light. Sori circular to elongate, superficial or sunken in lamina, in one row each side of midrib, receptacles sometimes prominent on adaxial surface of lamina.

Taxonomy — Oreogrammitis subevenosa was formerly regarded as a synonym of O. adspersa ( Copeland 1952, Parris 1983, 2007, 2010) but was later separated from it by Parris (2013). Here we recognize two species in Glabrigrammitis . Glabrigrammitis nuda is distinguished from G. subevenosa by broadly elliptic to elliptic sunken sori versus circular to broadly elliptic superficial sori. The former is endemic to Taiwan Island; the latter is in Thailand, Vietnam, Peninsular Malaysia, Java, Borneo, Philippines, Maluku, New Guinea, and Solomon Islands.

Figures

FIGURE 4. Glabrigrammitis nuda (Tagawa) Li Bing Zhang, X.M.Zhou, Jian Jun Yang & Parris.—A. Habit and habitat.—B. Habit.—C. Lower portion of plant showing rhizome.—D. Adaxial view of sterile lamina.—E. Adaxial view of portion of fertile lamina.—F.Abaxial view of portion of lamina showing sori (photo credit: Ralf Knapp).