128 FISSIDENTACE.ffi. 



15. Pissidens taxifolius Hedw. (Hypnum taxifolium L.) 



(Tab. XXI. C). 



The smallest of the lateral-fruited species, usually less than \ 

 inch high, rarely exceeding one inch ; dark green, often with a 

 tinge of reddish brown, branched from the base, suberect. Leaves 

 crowded, usually longest in the middle of the stem, oblong- 

 lingulate, broadly pointed and apiculate with the percurrent nerve, 

 not bordered ; inferior lamina ceasing abruptly at base ; cells as in 

 the last species, but less opaque and with thinner walls, marginal 

 cells not distinct, though those of the outer row are occasionally 

 more pellucid and slightly different in shape, regularly and almost 

 uniformly crenulate or finely serrulate from base to apex. 

 Autoicous, male flowers on short basal branches. Seta red, from 

 near the base of the stem, flexuose, rather long ; capsule equal and 

 suberect or variously inclined and gibbous, sometimes almost 

 pendulous ; lid longly rostrate ; peristome large, bright red. 



Hab. Woods, roadsides, etc. , usually on clay. Common. Fr. winter. 



Readily known, in its usual form, from the larger species by its shorter stems and 

 leaves ; under the microscope the percurrent or excurrent nerve and entire absence of 

 marginal band easily determine it. It is not a variable species except in the form and 

 direction of its fruit. 



Order VIII. GRIMMIACE^E. 



Plants of varying habit, most frequently in dense tufts or 

 cushions. Leaves in many rows, crowded, frequently hyaline- 

 tipped, ovate-lanceolate or rarely linear-subulate ; upper areola- 

 tion small, usually opaque and often 2 or 3-stratose, lower longer, 

 with the walls frequently sinuose. Capsule on a straight or 

 arcuate short seta, symmetrical or very slightly unequal, oval or 

 cylindric. Calyptra mitriform or cucullate, sometimes papillose, 

 smooth or sulcate. Peristome single, resembling that of Dicranum, 

 but without vertical stria?, less regularly cleft, the exterior plates 

 usually thickest and often transversely trabeculate. Male flowers 

 gemmiform. Almost entirely confined to rocks. 



The Order, as above defined, forms an exceedingly natural 

 one ; there is a great uniformity in habit, areolation, fruit, and 

 especially in peristome. The peristome of Orthotrichum and its 

 allies is of an entirely different character, and in other respects 

 nothing is sacrificed by separating the two Orders, an arrange- 

 ment which will also probably be found by the student to simplify 

 their study. 



