305 
series of three, sometimes of two, slender, straight, ascending, the 
ultimate rays 6’’-15’’ long or, occasionally, much longer in effort 
to branch again for an umbellate division of the fourth series, 
which may be perfectly realized. Frequently the primary 
division of the stem is only sub-umbellate owing to the displace- 
ment of one of the branches; on many plants there is a well- 
developed lateral flowering branch. Staminate flowers with the 
fertile, or in separate heads peduncled in the forks of the stem or 
main branches; pedicles slender, 1-24” long, four or five times 
times the length of the minute campanulate calyx, which is cleft 
little more than half way down into somewhat triangular-ovate 
rather obtuse lobes; flowering umbellets small, about 3/4” in dia- 
meter; petals obovate, heart-shaped, fully twice the length of the 
sepals, yellowish-green, filaments exserted, anthers bright yellow. 
Fruits very small, 3-5 in each umbellet, broader than long, and 
somewhat obovate in outline, measuring through the bristles 114’”— 
2” high, by 2-214” wide, evidently pedicelled, pedicels not over 
1” long, papillose with rudimentary bristles; bristles of the fruit very 
small and weak, rudimentary at base of pericarp, gradually length- 
ened above, but not exceeding 1”, and commonly half that size, 
not crowded, arranged in eight or ten rows which may be evident 
or obscure, curved at tip into a more open hook than in Mary- 
landica ; though sometimes slightly depressed-dilated at base, they 
commonly rise abruptly from the nearly even surface of the ma- 
ture carpel, which is of a dark or blackish color; fruit reflexed at 
maturity; styles abruptly spreading and recurved among the 
bristles, sometimes extending more than half way around the fruit. 
Seed rounded-oblong in cross-section, dorsal surface even, not at 
all sulcate or angled, commissural face plane; pericarp thin and 
membranous, closely investing the seed ; oil-tubes five, very small ; 
commissural scar linear. Rootstock much as in Marylandica, but 
not so stout and contractcd, the fibres less fasciculate, much more 
slender and fibrillose, and of a blackish instead of brownish color. 
The substance of the rootstock hasa fainter and altogether differ- 
ent odor. (Plate 242.) 
This plant when once known is in no danger of being con- 
fused longer with either Marylandica or Canadensis. It is clearly 
a perfectly distinct species, not even to be regarded as inter- 
mediate between the other two, nor as related to them by any 
nearer ties than those of acommon genus. Its nearest affinity is with 
Marylandica, with which it has been mainly confounded, notwith- 
standing that the general aspect of the two is strikingly dissimilar. 
To compare the superficiary characters, S. gregaria is a less robust 
plant, more widely branched and more leafy above, but with less 
