— 72 — 



TORTULA CAROLINIANA, NEW SPECIES 



A. Le Roy Andrews 



Tortula caroliniana n. sp. — Growing in extensive mats on the bark oi 

 trees. Stems somewhat matted below with radicles, with brown leaves, above 

 simple, with bright green leaves, which readily become brown with age. Plants 

 very short or sometimes more lengthened, up to about i cm. Stem in section 

 round, with central strand; outer 2-3 rows of cells gradually smaller and thicker- 

 walled than those within. Leaves obovate, normally about 2.5 mm. long, i 

 mm. wide in widest part, borders strongly reflexed in basal apex abruptly 



apiculate with costa only percurrent; costa slender, up to 50 [K in width in lower 

 part of leaf, brown, smooth on back, m section with two guide-cells and two ven- 

 tral cells nearly equally large adjoining them, dorsally of uniform stereid cells. 

 Leaf-cells at base smooth, rectangular, the outer ones narrow and somewhat 

 chlorophyllose, up to 50 x 10 \x, in region of costa larger, hyaline with brown 

 walls, up to 70 x 25 [Jl; cells of upper part of leaf irregularly roundish quadrate, 

 with fairly thick walls and distinct trigones, averaging about 14 [L in diameter, 

 in border region slightly smaller and with thicker walls, but not giving the im- 

 pression of a distinct border, papillose on both surfaces, the papillae mostly 

 crescent shaped,^ 3 [L or less from end to end of the crescent, normally 4 per cell 

 on either side, rarely more than 6, in smaller cells of border region often 2 or 3. 

 Papillae rather low in profile and quite independent of each other, the wall to 

 which they are attached not at all thickened, the outer wall of cell very slightly 

 bulging. 



Inflorescence and sporophyte not seen. Reproduction by means of very 

 numerous propagula, more or less cylindrical in shape, with rounded ends, pro- 

 duced from ventral surface of upper half of leaf blade,^ the cells from which they 

 originate generally slightly smaller than those surrounding them, often lacking 

 chlorophyll and with papillae less distinct or lacking. Propagula densely chloro- 

 phyllose, somewhat roughened on outer surface, divided by parallel planes at 

 right angles to the axis of development at intervals of 20-25 [^y these divisions 

 often further subdivided into 2 or 4 parts by planes at right angles, the subdi- 

 vision of adjacent segments in this case not necessarily conformable, the end 

 segments usually smaller and undivided. The number of primary divisions 

 varies with the length of the propagulum all the way up to 8, which is sometimes 

 but not often exceeded. The width of the propagulum varies up to about 45 

 (JL, the length is entirely variable, extending up to 200 [K or more. 



^In the illustration they are represented as too irregular in shape and somewhat too large. 

 Their shape is that of a perfectly regular crescent, except as they sometimes form a complete, but 

 again perfectly regular ring. This last tendency is stronger on the dorsal surface and also increases 

 with exposure of the plants to light and sun. 



^In the illustration they are slightly flattened down by the cover-glass; when undisturbed 

 they rise exactly perpendicular to the leaf-surface and are not at all confined to the immediate 

 apex of the leaf. The costa is represented as too broad in the figure. 



