POTTIACEAE. 



439 



3. EUCLADIUM Br. & Sch. 



Plants perennial, in dense mats, forming calcareous tufa; stems branching 

 erect and crowded ; leaves small, spreading, broadest at base, long-pointed ; 

 vein stout, percurrent; basal cells larger and clearer than the upper papillose 

 cells. Pedicel erect, exserted; capsule small, ovoid or eylindric; lid beaked; 

 calyptra cucullate; peristome single; teeth 16, per- 

 forate or split. [Greek, referring to the beautiful 

 branches.] A genus of 3 species. Type species: 

 Dry um verticillatum L. 



1. Eucladium verticillatum Br. & Sch. WHORLED- 

 LEAVED EUCLADIUM. (Fig. 480.) Plants growing in 

 dense bright green cushions, pale brown below; stems 

 up to 9" high, slender and brittle, rooting at intervals, 

 and branching repeatedly ; leaves small, in clusters at 

 the tops of the branches, base broad, with a few sharp 

 teeth, apex narrower, margins above flat, entire; vein 

 stout, ending in the rather blunt apex; basal cells 

 oblong, upper round and small, papillose. Pedicel 

 erect, slender; capsule ovoid-cylindric, erect or hori- 

 zontal ; calyptra cucullate ; lid beaked ; annulus nar- 

 row; teeth 16, more or less perforate along the 

 median line. 



On wet limestone in caves, often dripping with 

 moisture and hardened with lime deposits. Widely dis- 

 tributed in North America, Europe and Asia. 



4. GYHOWEISIA Schimp. 



iSmall plants, usually growing on limestone rocks; stems short with 

 a few short lanceolate or lingulate leaves, usually blunt, base broader hyaline, 

 vein single, ending below the apex ; upper cells round and dense, often swollen. 

 Usually dioicous. Pedicel erect, short and twisted; capsule small, ovoid or 

 eylindric; peristome more or less developed, usually falling with the lid; 

 annulus present; lid conic-apiculate or beaked. [Greek, in reference to the 

 twisted annulus.] A genus of about 14 species, found in subtropical regions, 



from Florida to Cuba, Jamaica and Porto Kico. Type 

 species: Gymnostomum tenue Schrad. 



1. Gyroweisia Barbula (Schwaeger.) Paris. 

 BLACK-FRUITED GYROWEISIA. (Fig. 481.) Plants sel- 

 dom more than 3" high, dark green, or almost black, 

 stemless, with a rosette of a few .basal leaves, which 

 are linear-oblong and twisted when dry; vein endirig 

 below the blunt apex; margins finely creuulate- 

 toothed, inrolled when dry; basal cells oblong, lax and 

 clear; upper cells round and swollen. Pedicel short, 

 erect ; capsules narrowly eylindric, straight or slightly 

 curved, mouth narrow ; lid conic, beaked ; annulus 

 present ; calyptra cucullate ; peristome usually falling 

 with the lid; teeth 16, bifid, and papillose; spores 

 smooth, minute, maturing in March and April. [Tor- 

 tula melanocarpa Mitt, of Challenger Report ; Gymno- 

 stomum Barbula Schwaegr.] 



On limestone usually associated with Tortula agraria. 

 Florida ; Cuba ; Jamaica ; Porto Rico ; South America. 



