366 LEUCODONTACEyE. 



1. Leucodon SCiuroid.es Schwgr. {Hypnum sciuroides L.) 

 (Tab. XLIX. J.). 



Primary stem slender, creeping, giving off numerous erect, 

 secondary stems, which are simple or slightly branched, cuspidate, 

 straight, terete and julaceous, with the leaves closely imbricated 

 all round, or frequently arcuate with the leaves secund and 

 homomallous, 1-2 inches high, rarely more. Leaves crowded, 

 dark green, erecto-patent, when dry erect and appressed, i-i£ 

 lines long, cordate-ovate, narrowed above and then rapidly 

 tapering to a narrow acumen, concave, longitudinally plicate ; 

 margin plane, entire, or minutely denticulate in the acumen ; 

 nerve none. Cells in the upper part vfry small, oval, longer and 

 elongate-elliptic in the acumen ; at mid-base narrow-linear , 

 extending about half-way up the leaf and gradually passing into 

 the oval ones ; at margins in the lower half of the leaf rounded, 

 dot-like, forming a broad band on each side, which is widest at 

 base. Seta about half-an-inch long ; capsule elliptic-oblong, 

 brown, lid conical. Dioicous. 



Var. /?. morensis B. & S. (Hypnum morense Schleich.). 

 Secondary stems and branches tall, thick, turgid; leaves wider; 

 pericha^tial bracts longer ; capsule cylindrical. 



Hab. Trunks of trees, rarely on rocks. The var. )3 rare. Fruit very rare, spring. 



Readily identified by the terete, often curved, usually cuspidate branches and 

 stems, with plicate, nerveless leaves. Pleuropus sericeus somewhat resembles its 

 more slender forms, but the leaves of that species are longer and narrower, nerved, 

 more deeply plicate, with longer, narrower cells. The lower leaves are often shorter 

 and more spreading, even when dry. 



The var. morensis is the most frequent form in the Mediterranean region ; forms 

 somewhat approaching it may not unfrequently be seen ; it is recorded by Schimper 

 from Craig Chailleach, but I am not aware that fertile plants have been found in this 

 country. 



The tips of the stems often produce numerous, gemmiform ramuli, which are 

 short, filiform, and minute-leaved, sometimes occurring in such quantities as to deform 

 the plant. 



A slender form with the branches long and arcuate, and the leaves decidedly 

 falcato-secund, is the forma falcata Boul. 



88. PTEROGONIUM Swartz. 



Primary stems creeping, stoloniform, giving rise to erect, 

 sub- dendroid secondary stems, unbranched at the base, with 

 numerous , crowded branches at the summit, all turned to one 

 side and curved. Leaves crowded, imbricated all round the stems 

 and branches, ovate-acu?ninate , faintly nerved. Upper areolation 

 smooth, narrowly elliptical or oval. Peristome double. Calyptra 

 sparingly hairy. 



