Cyperaceae |
| Perennial or annual. Stems bearing inflorescences
usually solid and triangular in transverse section,
rarely terete or jointed. Leaves usually in 3 rows,
mostly basal, either scale- or sheathlike, or linear and
grass-like, mostly withouth a ligule. Inflorescence
variable; from a terminal few-flowered spikelet to a
compound panicle with many spikelets, either naked or
with leaf-like involucral bracts. Spikelets unisexual or
bisexual, few- to many-flowered, often with many sterile
flowers. Flowers unisexual or bisexual, solitary within a
flume-like bract. Perianth reduced to hairs, bristles,
scales or absent, sometimes forming a sac (utricle)
surrounding the nut. Stamens usually 3, rarely 1-12 or
more. Ovary superiour, with 1 erect ovule; style 1;
stigmas 2 or 3; fruit a nut, either trigonous or
biconvex, often with a persistent beak. There are many
different interpretations of the Cyperoid flower. In this
account the flowers are considered to be basically
bisexual with a perianth reduced to scales or bristles;
the number of stamens in the flower is considered to be
3, in some cases reduced to one; many stamens arise by
the grouping of a number of one-stamened flowers. Generic
delimitation is problematic, the treatment adopted here
takes Cyperus in its broadest sense, and Scirpus
in a narrow sense (Eleogiton, Isolepis, Oxycaryum,
Schoennoplectus and Websteria are recognised
as genera). Unless stated the genera are assumed to be
helophyted, pollinated by wind (anemophilous), having
nuts as diaspores with unknown dispersal mechanisms. |
