458 TRANS. OF THE ACAD. OF SCIENCE. 
single, two-flowered heads; fruit and seed are unknown. I 
take it for a depauperate water form of our species, while 
Hooker, Fl. Bor. Am. 2, 191, unites it with J. wliginosus, 
which with him is what I have taken for J. alpinus; but 
that is also a 6-androus species. The botanists of Canada 
and of our northern border ought to find it again and clear 
up these doubts. 
I have already (p. 426) spoken of the great morphological 
importance of this plant, which connects the single-flowered 
with the head-flowered species, and proves, as certainly might 
have been expected beforehand, that no absolute difference 
exists between them; that the flowers in all of them are 
really lateral; that in the former only one flower is formed, 
while in the others a series of them, from two to an indefinite 
number, are developed in centripetal order. In our species a 
second flower is more commonly not present, and its place is 
occupied by a bud, which often, and especially later in the 
season, grows to a leafy excrescence (whence the name vivi- 
parus); sometimes even the first flower is replaced by a leaf- 
bud, and in rare instances a leaf-bud makes its appearance 
between two flowers as a third axillary organ. I have 
never seen more than two flowers, nor more than one leaf- 
bud in a head. Botanists who have the opportunity ought 
to investigate the variations in the inflorescence of this plant 
according to locality, season, or other circumstances. 
33. J. arTIcuLATUS, Linn.; that form of the Linnean spe- 
cies which was distinguished by Ehrhart as J. dampocarpus, 
and which is common in northern Europe, has a very limited 
range in North America. All the specimens I have seen 
came from the New England States (Boston, Pickering; 
Amherst, Tuckerman; and Providence and Nantucket, O/- 
ney) and from western New York (Penn Yan, Sartwell); to 
these La Harpe adds Newfoundland.—Stems densely cespi- 
tose from a creeping root-stalk, with us usually erect and 
about one foot high; panicle short, dense-flowered, spreading, 
brown ; sepals mostly equal, lanceolate acute and mucronate, 
or inner ones slightly longer and sometimes obtusish ; stamens 
about two-thirds the length of the sepals, and anthers as long 
as filaments; ovary acuminate, terminating in a style about 
half its length; capsule longer than the sepals, acute, or even 
rostrate, at least in all the American specimens seen by me, 
and imperfectly three-celled, the placente not meeting in the 
centre. Seeds obovate, obtuse at the upper, acute at the 
lower, end, and at both strongly apiculate ; 0.3 line or a little 
less long, and about half as much in diameter; reticulate, 
with are: finely cross-lineolate; 7 or 8 ribs visible. 
34. J. atpinus, Villars, Delph. 2, 233 ex Koch Syn. Germ. 
730; J. fusco-ater, Schreb. ex Kunth En. 38, 326, J. affinis, 
