Diplostichum longirostre

Diplostichum longirostre

Diplostichum longirostre (Brid.) Mont., Ann. Sc. Nat. Bot. ser. 3, 4:117, 1845.

Pterigynandrum longirostre Brid., Mant. Musc. 131, 1819. [Original material: Tristan da Cunha, coll. Aubert du Petit Thouars.]

Eustichia longirostris (Brid.) Brid., Bryol. Univ. 2:789, 1827.

Didymodon distichus Schwaegr., Spec. Musc. Suppl. 2(2):110, 1827, hom. illeg. [Original material: Madagascar, coll. Aubert du Petit Thouars.]

Diplostichum spruceanum C. Müll., Hedwigia 36:85, 1897. [Original material: Mt. Pichincha, Ecuador, coll. Spruce n. 1.]

Eustichia spruceana (C. Müll.) Par., Ind. Bryol. Suppl. 153, 1900.

Diplostichum distichum Card., Rev. Bryol. 40:19, 1913. [Based on Didymodon distichus Schwaegr., hom. illeg.]

Stems 1–3 cm high. Leaves to 1.2 mm long, 0.4 mm wide, usually equally wide on both sides at base; margin with small projections which sometimes are double at each cell juncture, projections weaker to nearly lacking toward tip; cells of lamina rounded to subquadrate, ca. 10 μm in diameter, with rather thick walls, a few scattered, narrower cells along margin; basal cells up to 20 μm long. Perichaetia 2 mm long. Setae ca. 2 cm long, yellowish. Capsule urn to 1.2 mm long. Operculum ca. 1.2 mm long.

MAS AFUERA: Q. Casas, bluff beside stream, H. & E. 145, near mouth, H. & E. 146 part, 222.

As delimited here the species occurs on islands of the South Atlantic and Indian oceans, Juan Fernandez, and northward in the Andes at least to Ecuador. While using the oldest species name in the genus, I nevertheless recognize some limitations.

Without seeing more material or types I can only suggest the following possible alignment. Juan Fernandez material has weak papillae on the lamina and the margins are only slightly serrulate distally. This most closely approaches the entire-margined condition described by Bridel-Brideri (1827) and is essentially like the fruiting part of isotype material of D. spruceanum C. Müll. Other South American material, including the nonfruiting pieces of the isotype of D. spruceanum, have stronger papillae and more strongly papillose margins. The proper name for such material seems to be Diplostichum jamesonii (Tayl.) H. Robinson, new comb. (basionym: Cymbaria jamesonii Tayl., J. Bot. 7:190, 1848). Specimens from Costa Rica (Valerio 310) and the Dominican Republic (Ekman 12006) show a slightly more robust plant with large, nonoverlapping leaves that are usually narrower on one side at the base. The only name that might represent this northern element is D. miradoricum C. Müll. The name previously used for Juan Fernandez material, D. poeppigii C. Müll., cannot be definitely placed without seeing type material.