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 EH. scaposus, DC., but 
strongly characterized as well by the smooth green scales of its 
involucre as by the presence of the floating leaves. 
MELAMPODIUM LoNSIPILUM. 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, 2-25 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 José 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 ait 
vided with longer appendages 
Sapazia MicHoacana. Pexcuninl, 2-3 feet high: stem slew : ne 
der, purple, hirsute-pubescent, somewhat branched, springing from — 
a short horizontal rootstock: leaves opposite, | sitearsiar soto 8 ser- 
£ 
