Andreaea sinuosa, sp. nov. (Musci: Andreaeaceae), from Alaska, British Columbia and Scotland

Abstract

Andreaea sinuosa has no close relatives and is characterized by narrowly lanceolate, ecostate leaves with incurved margins; small spores, 11-21 im, as small as any in the genus; and by basal leaf cells with sinuose walls (as in Racomitrium), which are not known for other ecostate Andreaeae. Very rare and widely disjunct in northwestern North America and northwestern Europe, it occurs in mountainous regions with an oceanic climate on exposed rock, often in snow-beds. A key to ecostate Andreaeae of North America and Europe is provided. During monographic study of the genus Andreaea, I found several collections, most named A. rupestris Hedw., that represent a new species. Andreaea sinuosa B. Murray, sp. nov. (Fig. 1-16) Parva, ecostata; folia anguste lanceolata, margine incurvata; sporae parvae, 11-21 Am diametro. Haec species differt ab omnibus ecostatibus congeneribus parietibus sinuosis cellularum laminae, similibus generi Racomitrio. Plants small, densely tufted but easily broken, green-brown, red-brown, purple-black or black; saxicolous. Protonemata persistent, consisting of stolon-like, yellowish, multiseriate filaments and uniseriate, brown rhizoids; few thallose appendages seen. Stems erect, rarely over 10 mm high, simple to sparingly branched, red-brown, cells frequently sinuose in surface view; in transverse section round, with round, thick-walled cells, central strand absent, outer cells usually slightly smaller than inner, with exterior walls bulging. Axillary hairs frequent, persistent, with 1 (rarely more) brownish, quadrate to short-rectangular basal cell and 1 (rarely more) at first hyaline, later brown, cylindric or clavate terminal cell, with breaks in thin outer wall. Scaleleaves frequent along lower stems, minute, about 0.25-0.30 mm long, lanceolate to ovate, apiculate, occasionally sparsely toothed from projecting cells. Leaves spirally arranged, sometimes appearing tristichous, larger distally, when moist slightly spreading, when dry erect, more or less appressed; narrowly lanceolate to linear-lanceolate, slightly curved to secund, acute or occasionally rounded, to 1.6 mm long, unistratose or with occasional small marginal or laminal bistratose areas; lamina about 22-28 im thick distally, 15-20 im thick proximally; bases oblong, slightly sheathing, narrowed to the straight insertion, usually strongly gibbous on one side only and with a conspicuous fold; margins conspicuously incurved from bases to apices, entire. Costa absent. Upper leaf cells irregularly rounded, oval or oblate, 10-14(16) /m long, 10-12 /m wide, with large, low, brown to white papillae that are more numerous centrally than marginally or apically; walls ? incrassate and collenchymatous, with micropapillae often visible in transverse section due to bulging of walls between adjacent cells. Laminal cells gradually larger and conspicuously pitted to sinuose towards the sheathing base, with papillae over lumina sparse and micropapillae over transverse walls between cells more conspicuous. Basal cells rectangular to oblong, 22-50 im long, 10-12 lim wide, lumina often scalariform, longitudinal walls incrassate, pitted and strongly sinuose, as in Racomitrium, trans0007-2745/86/189-194$0.75/0 This content downloaded from 157.55.39.104 on Mon, 20 Jun 2016 05:36:05 UTC All use subject to http://about.jstor.org/terms 190 THE BRYOLOGIST [Volume 89 .. :., I 4 2o 1-zzr p