Ceratophyllaceae |
| Entirely submerged perennial or sometimes annual.
Roots absent (even in the embryo) but branches sometimes
modified as 'rhizoids'. Stem branched but not more than
one branch at a node. Leaves whorled, (3-) 6-8 (-10) at a
node, rather rigid, often brittle, 1-4 times forked, with
2 rows of minute teeth along the ultimate segments, each
segment tipped by 2 bristles. Flowers unisexual, solitary
in the axil of 1 leaf in a whorl. Perianth of 8-12 linear
segments, united at the base. Stamens numerous; filaments
short or absent; connective prolonged at the apex. Ovary
superior, 1-locular; fruit a 1-seeded nut, tipped by the
persistent style and often with additional basal and
marginal spines, sometime also warty. Totally
submerged, rootless, free-swimming: hypohydrophilous,
stamens are liberated and dehisce floating just below the
water surface: diaspores relatively large and spiny nuts
or specialized buds, dispersal probably by animals and by
water: large populations may be troublesome blocking or
constricting water channals. |
