Evans: Genus of Hepaticae from Hawaiian Islands 103 



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Acromastigum gen. nov. 



Plants medium-sized, scattered among other hepatics, yellowish- 

 green, becoming brownish with age : stems stiff and wiry, mostly 

 ascending or erect, sparingly branched: vegetative branches of 

 three kinds : — terminal branches from the lateral segments, terminal 

 branches from the postical segments (flagella), intercalary branches 

 axillary to the underleaves (very unusual) : rhizoids not abundant : 

 leaves distant or subimbricated, transversely inserted, undivided : 

 underleaves a little smaller than the leaves, undivided : leaf-cells 

 with thickened walls : sexual branches intercalary, arising singly 

 in the axils of the underleaves*: 9 branch very short, its leaves re, 

 duced to the three to five rows of bracts ; perianth long and slender, 

 hypogonianthous, the three keels distinct except at the cylindri- 

 cal base, separated by grooves ; unfertilized archegonia borne at 

 the base of calyptra ; $ spike oblong ; bracts in several pairs, 

 strongly concave; antheridia occurring singly ; paraphyses wanting ; 

 bracteoles similar to the underleaves but smaller : sporophyte not 

 seen. (Name from axpov, summit, and fiaarfc, a whip or lash, 

 alluding to the flagella and their place of origin.) 



Acromastigum integrifolium (Aust.) 



Mastigobryum ? integrifolium Aust. Bot. Gazette, I : 32. 1875 

 Bazzania? integrifolia Evans, Trans. Conn. Acad. 8 : 225. 

 1892. 



Dioicous : general characters of stems and branches given 

 above : rhizoids whitish, simple or irregularly branched at the 



ends, very scanty on ordinary vegetative axes and occurring 



singly or in small clusters at the bases of some of the underleaves, 

 more abundant on the flagella and less definite in position : leaves 

 spreading widely from the stem, usually curved upward in the 

 outer parts, ovate from a broad base, obtuse or more commonly 

 acute, entire or nearly so, rarely with an indistinct angular tooth 

 near apex : underleaves strongly squarrose, ovate or oblong, 

 truncate or rounded at apex, entire or nearly so : leaf-cells with a 

 very thick verruculose cuticle and conspicuous often confluent 

 trigones but no intermediate thickenings : cell-cavities stellate : o 

 bracts very small and similar to ordinary leaves at base of branch 

 but becoming rapidly larger toward perianth : innermost bracts 

 broadly ovate, gradually narrowed from near the base, shortly 

 dentate or laciniate at apex (usually less than one fourth the 

 length) with slender teeth, otherwise entire or nearly so ; inner- 

 most bracteole similar ; perianth linear-fusiform, composed of a 

 single layer of cells except at the very base, cells more uniformly 



