M Ws 
"m 
150 DR. R. R. GATES: A STUDY OF NORTH AMERICAN 
no doubt been independently derived many times, as we see in Amianthium, 
Anticlea, and Allium within this group. It is more difficult to visualize the 
passage from a rootstock to a bulb than in the above case of dicecism. It is 
very difficult to believe that the passage is ever abrupt, and in certain plants, 
such as Amianthium, the condition appears to be somewhat intermediate, the 
bulbous condition not having been fully arrived at. 
Amianthium is perhaps more closely related to Schanocaulon, whose main 
distinguishing features are as follows :— 
Scheenocaulon, Amianthium. 
Fibrous-coated bulbs. Bulb-like rootstocks. 
Leaves basal, narrowly linear. Leaves linear, blunt-pointed, those of the 
stem much fewer and shorter. 
Flowers in slender spikes, or in spike-like Flowers larger, in cylindrical racemes with 
racemes with short pedicels. long pedicels. 
Perianth green, persistent, sepals and petals Perianth white, sepals and petals broad. 
narrow. j 
Seeds slender, nearly terete. Seeds thick, reddish brown. 
9. SCHCENOCAULON, A. Gray. 
The genus contains about twelve species, of which all but two are confined 
to Mexico and will not be considered here. These two are as follows :— 
1. Scu&NocAULON DUBIUM (Michx.) Small. 
S. dubium, Small, Fl. SE. Un. St. (1905) 250. 
S. gracile, A. Gray, in Ann. Lye. N.Y. iv. (1837) 127. 
Helonias dubia, Michx. Fl. Bor, Am. i. (1803) 213. 
In dry pine lands, Georgia and Florida. 
2. Scnawocauton DRUMMONDII, A. Gray; Hook. & Arn. Dot. Beechey 
Voy. (1841) 388. 
S. texanum, Scheele, in Linnæa, xxv. (1852) 262. 
On prairies, Texas and Northern Mexico. 
These two species, apparently discontinuous in their distribution, form an 
interesting pair :— 
S. dubium: compact portion of spike 5 mm. thick ; sepals oblong; capsules sessile. 
S. Drummondii: compact portion of raceme 10 mm. thick; sepals linear; capsules 
pedicelled. 
S. Drummondii is stouter in every part, having larger flowers and wider 
leaves. ©. dubium has apparently been derived from it by reduction. It is 
not a dwarf in the ordinary sense, but more like a miniature. The 
chromosome relations of these species would be worth looking into, 
