UND CUXM€CUK- 
MELANTHACEJÉ FROM THE GENETIC STANDPOINT. 151 
10. STENANTHIUM, Kunth. 
This genus as now recognized contains only two species. 
1. STENANTHIUM GRAMINEUM (Ker), Morong. 
S. gramineum, Morong, in Mem. Torr. Club, v. (1894) 110. 
S. angustifolium, Kunth, Enum. iv. (1843) 190. 
Helonias graminea, Ker, in Bot. Mag. (1813) t. 1599. 
Veratrum angustifolium, Pursh, Fl. Am. Sept. i. 242, ii. 747 (1814). 
Xerophyllum gramineum, Nutt. Gen. i. (1818) 235. 
Virginia to Kentucky, Missouri, Alabama, and Florida. 
bo 
. STENANTHIUM ROBUSTUM, S. Wats., in Proc. Am. Acad. xiv. (1879) 278. 
Pennsylvania and Ohio to South Carolina, Tennessee, and Missouri. 
These two species have been united by some writers, but S. robustum is no 
doubt worthy of independent recognition. It is larger and stouter, as the 
name indicates, and may be a tetraploid mutant or cell-giant from 
S. gramineum. In S. robustum the capsule is erect, in S. gramineum reflexed. 
The former has leaves 4-6 mm. wide; the latter, leaves 6-20 mm. wide. 
The capsules of S. robustum are also larger (10 mm. long, instead of 8 mm.) 
and the perianth is said to be usually green, while in S. gramineum it 
is usually white. 
The two species occupy nearly the same territory, S. robustum extending a 
little further north and not so far south. 
improbably hybrids. 
should be made. 
Intermediate specimens are not 
A careful anatomical comparison of these species 
The genus Stenanthium is closely related to Amianthium, which it resembles 
in foliage and with which it agrees in having bulb-like rootstocks. There 
are, however, conspicuous differences in inflorescence and flower-structure, 
as shown in the following comparison :— 
Amianthium, Gray. 
Leaves linear, blunt-pointed, stem-leaves 
few and short. 
Flowers perfect, white, in a dense terminal 
cylindrical raceme. 
Perianth-segments broad, obtuse. 
Stamens as long as or longer than the 
perianth-segments. 
Capsule 3-celled, dehiscent above the 
middle, the divergent lobes tipped by the 
subulate styles. 
Stenanthium, Kunth. 
Leaves linear, narrower, blunt - pointed, 
basal leaves less numerous. 
Flowers polygamous, white or greenish, in 
an ample terminal panicle. 
Perianth-segments narrowly lanceolate, 
acuminate, spreading. 
Stamens shorter than the perianth-segments. 
Capsule ovoid-oblong, 3-lobed, dehiscent to 
base, the lobes with short, slightly 
divergent beaks. 
The paniculate inflorescence and narrow acuminate petals of Stenanthium 
are its most striking features. 
The change in the petals might represent a 
single variation, but it is difficult to say whether one or two germinal changes 
could transform the racemose inflorescence of Amianthium into the loose 
