OF ARTS AND SCIENCES. 173 



decidedly spatulate leaves, and the absence of the coarse spreading 

 pubescence. 



Erigeron heteromorphus. Amphibious, glabrous throughout : 

 stems dark-colored, subsimple, rooting for some distance along a 

 decumbent base : leaves of two very distinct forms, those of the 

 terrestrial specimens three-lobed to the middle, sessile by a cune- 

 ate base, 2 inches long, an inch or more broad; the lobes lacini- 

 ately cleft: leaves of the sterile aquatic stems linear, elongated, 

 subentire or more or less divided, 4 inches or more in length: 

 heads including the rays 7-8 lines in diameter, borne singly on 

 peduncles 3-4 inches in length: involucre of subequal moderately 

 imbricated flat smooth green subulate scales with very narrow 

 scarious margins : rays about 50, narrow, pure white. — Growing 

 from calcareous tufa, more or less submerged, Cascades of the Con- 

 cepcion River near Micos, San Luis Potosi, December, 1891 

 (n. 3963). A remarkable species near E. scaposus, DC, but 

 strongly characterized as well by the smooth green scales of its 

 involucre as by the presence of the floating leaves. 



Melampodium longipilum. A span or more high, cymosely 

 branched almost from the base : stem rather stout, the young in- 

 ternodes white with soft long spreading hairs, the older parts 

 pilose but much less densely so: leaves ovate or somewhat rhom- 

 bic, obtuse or rarely acute, contracted at the base and narrowly 

 connate, entire, appressed-pubescent, punctate, 2-2^- inches long, 

 half as wide : peduncles slender, very pubescent : bracts of the in- 

 volucre distinct, obovate, pointed, hirsute over the whole outer 

 surface: rays about 10, deep yellow, 2-3 lines in length: fertile 

 bracts laterally tuberculate-roughened, bearing a small acuminate 

 recurved appendage at the summit : disk somewhat elevated in the 

 centre. — San Jose Pass, San Luis Potosi, July, 1890 (n. 3639). 

 This plant stands very near M. divaricatum, DC, of which it may 

 possibly prove to be a well marked variety. It differs, however, 

 in its very hairy stem, and in its involucral bracts, which are not 

 only narrower and more acute, but are pubescent-hirsute over the 

 entire outer surface, instead of being merely ciliate, as in M. divari- 

 catum. Furthermore, the leaves are entire and incline to be more 

 obtuse, while the fertile bracts are very tuberculate and are pro- 

 vided with longer appendages. 



Sabazia Michoacana. Perennial, 2-3 feet high: stem slen- 

 der, purple, hirsute-pubescent, somewhat branched, springing from 

 a short horizontal rootstock : leaves opposite, ovate-lanceolate, ser- 



