Oenanthe fluviatilis (flab) Coleman
River Water-Dropwort
NOMENCLATURE
Oenanthe: see 0. crocota
Dropwort: see 0. aquatica
OTHER NAMES: river dropwort.
BOTANICAL DESCRIPTION
TYPE: glabrous perennial. Hyd. HEIGHT : 100cm
ROOTS: young plants: tuberous roots, disappearing as stem elongates. Fibrous roots
then develop at the nodes. Propagation by detached fragments.
STEMS: hollow, submerged & ascending or erect.
UMBELS: compound, leaf opposed and terminal, with 5-10(15) smooth or slightly
scabrid rays 1-3cm long. Peduncle < than rays.
LEAVES : lower submerged 2-pinnate, with cuneate segments deeply cut into linear to filiform
lobes. Aerial leaves 1-3 pinnate, with shallowly lobed segments 10mm, ovate to suborbicular,
lobes ovate, obtuse or subacute. Cuneate at base. Petiole with a sheathing base.
BRACTS: 5 subulate. Bracteoles 5-8 linear-lanceolate.
FLOWERS: white. Male and Hermaphrodite. Sepals lanceolate, acute,
persistent, outer petals scarcely radiating, styles forming a stylopodium. Fl. 7-9.
FRUIT: 5-6.5 mm, cylindrical. Commisure broad. Mericarps with prominent slender ridges.
Carpophore present. Vittae solitary. Styles 1/4 > as fruit, divergent. Stigma a small knob. 2n=22*.
HABITAT: slow flowing water.
DISTRIBUTION: native, local. S.E. England. E.& C. Ireland.
One locality in Wales. W. Europe.
POISONOUS PRINCIPLES : See. 0. aquaticum.
