10 Evans : Hepaticae of Puerto Rico 



rows at the base of the lobe, 25 // long, 21 // wide : underleaves 

 distant, orbicular, 0.2 mm. long, broadly cuneate at the base and 

 bearing a distinct radicelliferous disc, bifid about one half with 

 erect lobes, rounded to acute at the apex, and a narrow and usu- 

 ally acute sinus, margin entire or rarely angular-dentate on the 

 sides : inflorescence autoicous : 9 inflorescence usually borne on 

 a short branch (with only one or two pairs of leaves), innovating 

 on one side, the innovation simple or again floriferous ; bracts 

 obliquely spreading, complicate, the lobe plane or nearly so, 

 oblong-ovate, 0.75 mm. long, 0.35 mm. wide, slightly falcate, 

 mostly rounded at the apex, margin entire, keel narrowly winged, 

 lobule ovate, 0.35 mm. long, 0.17 mm. wide, obtuse to acute at 

 the apex, margin entire ; bracteole convex when seen from below, 

 slightly connate with both bracts, orbicular, 0.55 mm. long, apex 

 broad, varying from rounded and undivided to sharply and acutely 

 bidentate, margin usually entire, sometimes irregularly dentate in 

 the upper part ; perianth about half exserted, obovate in outline, 

 0.75 mm. long, 0.45 mm. wide, somewhat compressed, the lateral 

 keels sharp, antical surface plane or with a very indistinct keel in 

 the upper part, postical keel broad and two-angled, apex broad, 

 truncate or slightly retuse, beak short, surface smooth or slightly 

 roughened from projecting cells, especially along the keels : 

 inflorescence occupying a short branch or terminal on a longer 

 branch, sometimes proliferating from the apex ; bracts in from two 

 to ten pairs, imbricated, strongly inflated, shortly bifid with an 

 arched keel, the lobe rounded at the apex, the lobule more or less 

 pointed ; bracteoles one or two at the base of the spike, similar to 

 the underleaves ; antheridia in pairs : mature sporophyte not seen 



(PLATE I, FIGURES 1 0-2 5). 



On bark of trees. El Yunque, Evans {29). The species has 

 also been found in Cuba, at the base of the El Yunque Mountain, 

 Baracoa, by Underwood & Earle, and no. 34.6 of these collectors 

 may be designated the type. No other localities for the plant are 

 definitely known at the present time. 



The writer's account of R. flagelliformis is drawn from what 

 may be considered the normal condition of the species. Under 

 some circumstances, however, the appearance of the plants is com- 

 pletely altered, owing to the development of peculiar organs of 

 vegetative reproduction. These consist of modified leaves, which 

 are borne on the ascending or upright prolongations of prostrate 

 branches. Sometimes a flagelliform branch of this nature repre- 

 sents the continuation of an ordinary leafy axis (figure 23), some- 



