C E R A T O P H Y L L UM fubmerfum.
Unarmed Hormvort.
M O N O E C I A Polyandria.
G en. Char. Male. Cal. in many divilions. Cor.
none. Stam. 16 to 20.
Female. Cal. in many divifions. Cor. none.
Stigma nearly feffile. Seed folitary, coated.
Spec. Char. F ru it d e ftitu te o f fpines.
Syn. Ceratopbyllmn fubmerfum. Linn. Sp. PI. 1409.
With. 441. Hull. 21 i. FI. Dan. t. 510.
C. demerfum (2. Hudf. 419.
Hydroceratophyllon folio laevi, odto cornibus armato.
Vaill. Mem. de TAcad, des Sciences (German edition)
299. t. 15./. 2. Dill, in Raii Syn. 135.
D I L L E N I U S mentions his finding this plant, with
Mr. Manningham, in ditches by the road from Chichefter to
Selfey ifland. Our fpecimen was gathered near Yarmouth by
Mr. D. Turner, flowering in September.
Root perennial. Whole plant floating under water, much
branched, flender. Leaves about 8 in a whorl, forked twice
or thrice, their fegments linear, acute, fpreading, fometimes
toothed. Flowers axillary, feffile, folitary, male and female
on the fame plant. Calyx green, in many deep fegments.
Antherse large, roundiffi, gibbous, nearly feffile, toothed at
the top, fpeckled with red. Germen in a feparate flower,
with a calyx like that of the male, ovate, acute, fmooth,
beaked, with a feffile fimple ftigma. Fruit without fpines,
containing one large, oval, comprefled feed.
This fpecies is certainly to be diftinguifted from the more
common C. demerfum by its fruit being unarmed, not furniihed
with 3 long divaricating thorns. The. leaves being twice or
thrice divided, toothed or entire, on which Vaillant founded
his diftindtions, are variable circumftances, as Haller difco-
vered by fpecimens fent him from Paris. Linnaeus appears to
have not well underftood the two fpecies. We intended to
have publifhed both at the fame time/ but having fought in
vain this feafon for the fructification of the common one, we
would not keep back fo little known a plant as that here exhibited.