Cololejeunea tamasii (Lejeuneaceae, Marchantiophyta), a new species from Panama Author Schäfer-Verwimp, Alfons text Phytotaxa 2012 2012-07-17 60 1 9 12 http://biotaxa.org/Phytotaxa/article/view/phytotaxa.60.1.2 journal article 276112 10.11646/phytotaxa.60.1.2 bd0875e1-2d0e-4e4e-a901-b7461b889e06 1179-3163 5061674 Cololejeunea tamasii Schäfer-Verwimp sp . nov . ( Fig. 1 ) The new species is characterized by its suborbicular leaf lobes, crenulate-denticulate lobe margins, the rough dorsal surface of the leaf lobes and the two-celled lobule. This combination of characters is quite distinct and separates it from all congeners. Type:— PANAMA . Chiriqui : Cordillera de Talamanca , Boquete, Ostseite des Vulkan Baru , Regenwald entlang der Erdstrasse zum Sendero Los Quetzales, epiphyll, 1880 m , 8°51.0'N , 82°29.9'W , 7 April 2010 , A . Schäfer-Verwimp & I . Verwimp 30992 ( holotype JE !; isotype EGR !) . Small and delicate whitish green plants growing as scattered shoots on living or dead fern fronds, tightly appressed to substrate, with leaves (500–) 540–750 µm wide. Stems 2–5(–7) mm long, in lower part of plant 30–40 µm , increasing further upwards to (40–) 50–60 µm in diameter, composed of one medullary and 5 cortical rows of cells of which one forms the ventral merophyte; the cortical cells rectangular, the largest ones reaching 20–30 × 60–80 µm ; very rarely branched (only one small branch seen, shorter than laeves of main shoot), branches of the Lejeunea- type ; rhizoids abundant, fasciculate, hyalin. Leaves usually contiguous to slightly imbricate, more rarely somewhat distant, obliquely spreading, often weakly so and nearly at an angle of 90° to the stem, suborbicular to broadly ovate, with rounded to (more rarely) slightly acute apex, to (340–)375–420(–450) µm long and (300–)340–380(–405) µm wide, plane, the bases rounded, the antical base partly to completely covering the stem; the first 3–5 developed leaves always reduced, the first one sometimes to a few cells, and without lobules; lobe surfaces in upper 2/3–4/5 rough and margins irregularly crenulatedenticulate from conically protuberant cells exept at lobe base; lobe cells varying in shape and size, continuously decreasing in size from base to central lobe and margin, the basal cells 5–6-angular and up to 30 × 60 µm (in some leaves the largest basal cells ocelli like), median cells in the same shape than basal cells, 10–20 × 18–28 µm , marginal cells very irregular in shape (triangular, square, rectangular or asymmetrically 4–5-angular, the smallest about 8 × 10 µm , the cells in central and basal part often with small trigones and rarely with indistinct intermediate thickenings. Lobule seemingly always reduced to two cells, 30 × 50 µm , the distal cell crowned by the hyaline papilla which is about 6 × 10 µm . Style obviously lacking. Oil bodies numerous, 10–20 or more per cell, small, 1–1.5 × 1.5–2 µm with somewhat roughened, not glistening surface. Discoid gemmae abundant on dorsal and ventral leaf surfaces, the well-developed ones more or less 6- angular, consisting of 16–18(–20) cells, each 8–10 × 8–12 µm , and reaching up to (70–)80 × 90(–100) µm; most of the gemmae seen still in initial stages of development. Gynoecia and androecia not seen. FIGURE 1. Cololejeunea tamasii Schäfer-Verwimp. A. Plant in dorsal view, with gemmae. B. Part of stem with leaf lobe and lobule, ventral view. C. Cross section of stem, 50 µm in diameter. D, E. Upper marginal cells of leaf lobe. F. Gemma. G. First leaves of a plant arising from gemma, ventral view. H. Detail of stem in ventral view, with rhizoides and lower part of leaf lobes with lobules and hyaline papillae. I. Young plant, ventral view. J. Young plant, dorsal view. K. Detail of uppermost leaf of plant. L. Lower central leaf cells with oil bodies. Scale: A = 350 µm, B, D, F, G, H, K = 100 µm, C = 75 µm, E = 40 µm, I, J = 400 µm, L = 20 µm. All figures drawn by the author (all from the holotype). Etymology:— The species epithet is dedicated to Dr. Tamás Pócs from Eger , Hungary , outstanding bryologist and an expert on epiphyllous Lejeuneaceae . Ecology and distribution:— Cololejeunea tamasii is known only from the type collection, at a roadside within a protected area of lower montane rain forest where secondary woody vegetation was dominant. The plants were growing epiphyllous on leaves of shrubs in a humid environment, half exposed to sunlight and therefore drying up periodically. The type locality itself may be destroyed in the near future as woody vegetation along the road is cleared periodically. However, as a pioneer species C. tamasii , though easily overlooked due to its small size, may possibly be found at similar sites elsewhere in Panama or Central America.