Macromitirum eddyi B. C. Tan & Shevock, 2015

Shevock, James R., 2015, Species of Macromitrium (Orthotrichaceae) New to the Mindanao Region and the Philippines with One Species New to Science, Proceedings of the California Academy of Sciences 62 (21), pp. 541-549 : 542

Macromitirum eddyi B. C. Tan & Shevock , sp. nov.

Figures 1–3.

HOLOTYPE: Papua New Guinea: Milne Bay District, Raba-Raba Sub-district, bottom of scarp of Tantam Plateau, Mt. Suckling , 1645 m., in shaded forest, common on wood, 20 Jul 1972, coll. P. F . Stevens [ LAE 55716 ] ( BM!; isotypes, CANB, E, L, LAE) . PARATYPE: Philippines: Mindanao Island: Bukidnon Province, on access dirt road to trail less than 0. 5 km above Lantapan Village toward Mt. Dulang-Dulang in Kitanglad Range Natural Park, on trunk of Gmelina in disturbed forest near cultivated field, 20 Apr 2014, Shevock 44672 ( CAS; isoparatype, CMUH, NY, UC) .

The new species can be identified easily using the key to the species of Macromitrium published in Eddy (1996). Morphologically the new species is identified by its slender and long branches with leaves arranged in five straight, longitudinal rows, when wet. Other diagnostic characters include leaves with acute to acuminate apices, percurrent to shortly excurrent costae, papillose upper leaf cells, and tuberculate lower leaf cells. In addition, the basal leaf cells are thick-walled with straight to curved lumina.

Below we reproduce verbatim the species description prepared by Eddy (1996) in whose honor we name this new species in recognition of his great contribution to our knowledge of Malesian mosses. Additionally, we include herewith photographs of the specimen of the Philippine paratype to complement the nice illustration of what is now M. eddyi that appears in Eddy (1996).

“Plants yellowish, slender, with elongate, sparingly ramifying branches up to 5 cm long. Leaves closely set, squarrose-recurved and markedly pentastichous when moist, erect and appressed with crisped upper limbs when dry, rendering the branches string-like in appearance; triangular lanceolate, canaliculate, finely acuminate, up to 3 mm long; apex finely acute, pellucid. Costa percurrent to short excurrent. Upper lamina cells small, isodiametric, ca 6–9 µm diameter, densely pluripapillose and obscure; lower lamina cells elongate with strongly thickened walls and narrow, straight lumina, conspicuously tuberculate. Perichaetial leaves narrowly triangular-lanceolate, plicate, very finely acuminate and filiform-pointed. Seta short, about 3 mm long, smooth; capsule ovoid, smooth, small, the urn about 1 mm long and 0. 8 mm wide; peristome of pale, rather fugacious, triangular exostome teeth; calyptra naked.”

Figures

FIGURE 1. Macromitrium eddyi B.C. Tan & Shevock from the holotype, Stevens 55716 (BM). A. Leaf apex with percurrent costa of elongate cells and upper laminal cells multipapillose. B. Leaves. C. Lower laminal cells elongate with thickened walls and narrow, straight to somewhat curved lumina cells conspicuously tuberculate. Scale bars: A, C: 5 µm, B. 0.5 mm.

FIGURE 2. Habit of Macromitrium eddyi stems in a dry state. Shevock 44672 (CAS).

FIGURE 3. Growth habit of Macromitrium eddyi from Shevock 44672 (CAS).