364 EVANS [310] 



the branches apparently arising in the axils of ordinary leaves : rhi- 

 zoids sometimes numerous, sometimes few or none : leaves distant or 

 subimbricated, closely appressed at the base, widely spreading above, 

 complicate-bilobed with a distinct strongly arched keel less than half 

 the length of the postical lobe ; antical lobe erect-spreading, arching 

 across the axis and sometimes beyond, ligulate, rounded at the apex, 

 subentire or sometimes sharply and irregularly dentate at the apex, 

 and more rarely at the decurrent base; postical lobe longer and 

 broader, widely spreading, oblong or obovate, obtuse or rounded at 

 the sharply and irregularly dentate apex, margins otherwise subentire 

 though sometimes sharply ciliate-dentate at the short-decurrent base ; 

 apical teeth mostly one or two cells long; basal teeth, when present, 

 each consisting usually of a single pointed cell : median leaf-cells with 

 thin walls and very distinct trigones sometimes becoming confluent, 

 marginal and submarginal cells with more uniformly thickened walls ; 

 cuticle varying from strongly verruculose to nearly smooth : 9 inflores- 

 cence borne on a principal branch, sometimes with one or two inno- 

 vations ; bracts in a single pair, similar to the leaves but more erect and 

 smaller, clasping the base of the perianth, postical margin varying from 

 entire to finely serrate ; perianth ovoid-cylindrical, gradually narrowed 

 toward the mouth, deeply plicate throughout with about 16 sharp folds 

 separated by narrow grooves, terete or slightly flattened, mouth irregu- 

 larly lacerate, the divisions variously curved and contorted, finely cil- 

 iate, each slender cilium ending in a long row of cells : androecium 

 intercalary, bracts imbricated, in many pairs, similar to the leaves but 

 saccate at the base and with more erect antical lobes ; antheridia 2-6 

 in each axil ; paraphyses numerous, variable in shape but most fre- 

 quently linear, entire, often variously curved, one to three cells wide 

 in the middle : gemmae broadly fusiform, mostly two-celled, occasion- 

 ally produced both by sterile and sexual plants at and near the apices 

 of the leaves : mature sporophyte unknown. 



Stems 0.4-0.5 mm. in diameter, postical lobes of leaves 22.5 mm - 

 long, 0.8 mm. wide, antical lobes 1.21.7 mm - l n g 0.40.5 mm. 

 wide, leaf-cells at apex of leaf 14 p. in diameter, in the middle 16-23 

 [i long, 16 fi. wide, at the base 45 x 16 p, perianth 3.5-4.2 mm. long, 

 9-1.4 mm. in diameter, gemmaa 18 x 14 [* 



Orca (T. 1492, in part) ; Farragut Bay (B. & C. 619) ; Hall Island 

 (T. 1478). New to America. 



D. pltcata was described by Lindberg from specimens collected on 

 the island of Sachalin in eastern Siberia and was also reported by 

 him from two stations in Amur. Quite recently Herr Stephani has 



