Evans : Hepaticae of Puerto Rico 279 



substratum, irregularly pinnate, the branches obliquely spreading, 

 usually short but otherwise similar to the stem : leaves imbricated, 

 the lobe more or less convex and inflexed at the apex, falcate- 

 ovate, 0.85 mm. long, 0,6 mm. wide, antical margin nearly straight 

 near base and stretching partly or wholly across axis, then some- 

 what curved to the apex, postical margin straight or nearly so, 

 apex broad but usually acute, margin coarsely and irregularly 

 toothed in the apical region, teeth mostly 8 to 10, variable in size, 

 the smallest consisting of single projecting cells, the largest about 

 three cells long and two cells wide at the base; lobule nor- 

 mally of the spherical type but often poorly developed, 0.25 mm. 

 long, 0.2 mm. wide, hyaline papilla in a distinct depression, apical 

 sinus very short and almost straight; utriculi occasionally 

 present; cells of lobe averaging 19/^ at the margin, 2"^ ft in the 

 middle and 46 x 28// at the base, trigones large and often con- 

 fluent, triradiate and rounded at the ends of the rays, intermedi- 

 ate thickenings occasional, subrotund in outline ; ocelli usually 

 absent but sometimes occurring singly at the base of the lobe : un- 

 derleaves distant, orbicular, 0.35 mm. long, bifid about one half 

 with erect triangular lobes separated by an acute to obtuse sinus, 

 margins entire or vaguely crenulate or angular on the sides : in- 

 florescence diolcous : female branch variable in length, sometimes 

 much abbreviated, the flower subtended by one or rarely two sim- 

 ple and sterile innovations; bracts complicate, obliquely spread- 

 ing, the lobe ovate, r.r mm. long, 0.7 mm. wide, acute^ antical 

 margin more strongly curved than the postical, irregularly 

 spinose-dentate* except near the" base, the teeth mostly 10 to 20, 

 lobule lanceolate to narrowly ovate or oblong, 0.75 mm. long, 

 0.25 mm. wide, margin toothed but with relatively fewer teeth 

 than the lobe, apex acute to obtuse ; bracteole connate on both 

 sides, ovate, 0.75 mm. long, 0.4 mm. wide, bifid about one third 

 with erect, triangular and acute lobes and a narrow sinus, margin 

 as in the bracts but with smaller and fewer teeth ; perianth im- 

 mersed (except the horns), obovoid, i mrfi. long, 0.5 mm. wide, 

 surface roughened by the convex cells, especially along the keels, 

 beak short, horns about half as long as the main body of the 

 perianth (0.35 mm.), contracted near the base, inflated and en- 

 larged toward the rounded or bluntly pointed apex, more or less 

 compressed, smooth, the two postical horns obliquely spreading, 

 the two lateral widely spreading : (^ inflorescence usually occu- 

 pying a short branch, more rarely terminal on a longer branch; 

 bracts in one to six pairs, inflated, shortly and subequally bifid 

 with obtuse divisions and strongly arched keel ; bracteoles at base 

 of spike, similar to the underleaves but much smaller; antheridia 

 single orin pairs: mature sporophyte not seen. (Plate 19, figures 

 l-ii.) 



