Seirpus. | LXXXVIII. CYPERACEA. 485 
extending into central Asia, and in western Europe to the Loire and 
Belgium, and here and there into central Europe. Jn Britain, only in 
North Devon and the Channel Islands, 7. late in summer. 
11. S. pungens, Vahl. (fig. 1102). Sharp S.—Very near S. triqueter, 
but a rather smaller plant; one or two of the sheaths bear narrow, 
keeled leaves 1 to 3 inches long, the spikelets are few (usually 3 to 6), 
all sessile, in a close cluster; the stiff, triangular, outer bract continuing 
the stem as in S. triqueter. 
In bogs, marshes, and on the margins of pools, chiefly in North 
America and the West Indies, but occurs in western Europe, and is 
found on the sandy banks of St. Ouen’s Pond, in Jersey. Fl. swmmer, 
rather late. 
12. S, triqueter, Linn. (fig. 1103). 7Z'tangular S.—Rootstock creep- 
ing. Stems acutely triangular, 2 or 3 feet high, leafless, except that 
the one or two loose sheaths at the base bear a short lanceolate blade, 
from a couple of lines to near an inch long. Spikelets usually 8 or 10 
or even more, the central ones sessile, the others stalked, forming a 
compound lateral cluster or umbel; the stiff, triangular outer bract 
continuing the stem for an inch or more. Each spikelet is ovoid, 4 or 5 
lines long; the glumes brown, broad, usually notched or fringed at the 
_ top, with a minute point. Hypogynous bristles about 5. Style 2-cleft. 
Nut smooth and shining. 
In marshes, and edges of pools, in central and southern Europe, ex- 
tending eastward to eastern Asia and Australia, and northward chiefly 
in western Europe to Denmark; also found in America. Rare in 
Britain, and limited to the banks of tidal rivers from the Thames to 
Cornwall. fl. late in summer. 
13. S. lacustris, Linn. (fig. 1104), Lake S.—Rootstock creeping, 
with stout, erect stems, from 2 or 3 to 6 or 8 feet high, cylindrical at 
the base, gradually tapering upwards, and sometimes obtusely triangular 
near the top, with a single short leaf near the base. Spikelets ovoid or 
oblong, 3 to 6 lines long, rather numerous, in a compound lateral umbel 
or cluster, the outer bract continuing the stem. Glumes numerous, broad, 
brown, fringed at the edge, notched at the top, with a little point in the 
notch. Hypogynous bristles 5 or 6. Style 2- or 3-cleft. Nut smooth. 
On the margins of lakes and ponds, and in watery ditches, in Arctic, 
temperate and tropical regions over the globe. Abundant in Britain. 
Fl. summer, Two varieties are often distinguished as species, S. lacustris, 
with a 3-cleft style and smooth glumes, and 8S. Tabernemontam, Gmel. 
(S. glaucus, Sm.), with a 2-cleft style and raised dots on the glumes; but 
these characters are very inconstant, and there are often 2-cleft and 3- 
cleft styles in the same spikelet. The name of S. Duvalii or S. carinatus, 
Sm., is sometimes given to a variety of S. lacustris with the stems rather 
more triangular at the top, sometimes to a slight variety of S. triqueter. 
[There are three principal British forms of this species, S. lacustris 
proper, with terete green stems, leaves often floating, ciliate anther- 
tips and compressed nuts; S. Zabernceemontani, Gmel., with glaucous 
terete stems, scabrid glumes, glabrous anther-tips, and 3-gonous nuts ; 
S. carinatus, Sm., with green stems obtusely three-angled above, glabrous 
anther-tips, and compressed nuts. This last occurs on tidal river banks 
in the south of England only.] 
14, S. maritimus, Linn. (fig. 1105), Sea S.--Rootstock creeping. 
