170 DR. R. R. GATES : A STUDY OF NORTH AMERICAN 
Since Schenolirion, Hastingsia, and Chlorogalum form a group of three 
allied genera we may ‘compare the last two as follows :— 
Hastingsia. 
Bulbs white-coated. 
Leaves narrower. 
Perianth-segments lax and scarious, closely 
3-nerved., 
Style short. 
Flowers white or greenish, in densely 
many - flowered sparingly panicled 
racemes, 
Anthers versatile. 
Chlorogalum. 
Bulbs with membranous or densely fibrous 
coats. 
Leaves with undulate margins. 
Perianth-segments at length twisted over 
the ovary, distinctly 3-nerved. 
Style long, deciduous, 
Flowers white, pinkish or purplish, in loose 
paniculate racemes, 
Anthers versatile. 
Of these three genera, Schwnolirion occupies the Southern States from 
Florida to Texas, while Chlorogalum occurs in the greater part of California, 
and //astingsia is found in Northern California and adjacent Oregon. Itis 
difficult to trace the steps by which these genera have become separated. 
Hastingsia appears to be more closely related to Schanolirion despite its 
western position. In such cases, as in those of bifurcated genera with 
eastern and western species, it seems necessary to assume that the ancestors 
originally occupied a more northerly position and that the eastern and 
western forms became separated as they were driven southward by the ice. 
In the central plains area, plants of this group failed to find suitable habitats, 
at least after the plains took on their present aspect, and so only eastern and 
western forms, variously modified, have persisted to the present time. 
Another monotypic genus, represented by Hemiphylacus latifolius, S. Wats.*, 
in Northern Mexico, belongs with this group. Among its peculiarities the 
most interesting are (1) the tuberous roots, (2) the filaments adnate to the 
perianth-segments for half their length, (3) only the inner and shorter ones 
bearing anthers, which are versatile, rounded, introrse, and (4) the scarious 
l-nerved perianth-segments. 
20. CHLOROGALUM, Kunth. 
l. CHLOROGALUM POMERIDIANUM (Ker), Kunth. 
C. pomeridianum, Kunth, Enum. iv. (1843) 682. 
C. divaricatum, Kunth, l. c.; Torr. Bot. Mex. Bound, (1859) 218, t. 60. 
Scilla pomeridiana, DC. in Redouté, Lil. (1816) t. 421. 
Anthericum pomeridianum, Ker, in Bot. Reg. (1821) t. 564. 
Phalangium pomeridianum, D. Don, in Sweet, Hort. Brit. ed. 1, 416 (1827). 
Ornithogalum divaricatum, Lindl. Bot. Reg. xxviii. (1842) t. 98. 
Laothoe pomeridiana, Rafin. Fl. Tellur. iii. (1886) 53. 
L. divaricata, Greene, Leaflets Bot. Obs. i. (1904) 91. 
California, from Mendocino Co. southward to San Bernardino Co. 
* [n Proc. Amer. Acad. xviii. (1888) 164. 
