The flowers in this family are _hypogynous_ and have in part the
general monocotyledonous type with 5 trimerous whorls completely
developed in a regular hermaphrodite flower, and in part the flowers
so much reduced that the type is very difficult to trace. On the one
hand the family is well developed and has capitate inflorescences
(_Eriocaulaceæ_) and on the other hand it is distinctly reduced
(_Centrolepidaceceæ_). This family has taken its name from the fact
that the ovule is not, as in the Liliifloræ and nearly all other
Monocotyledons, anatropous, but _orthotropous_, so that the embryo
(βλάστη) becomes placed _at the end of the seed opposite_ (ἐναντίος)
_to the hilum_. Large, mealy endosperm.--The orders belonging to this
family are by certain authors grouped with the _Bromeliaceæ_ and
_Pontederiaceæ_, etc., into one family, FARINOSEÆ, so named on account
of the mealy endosperm, the distinguishing character of the Liliifloræ
then being that the endosperm is fleshy and horny.
Order 1. =Commelinaceæ.= The complete Liliaceous structure
without great reductions in the number of whorls, but with
generally few ovules in each loculus of the ovary, is found in
the Commelinaceæ, an almost exclusively tropical order with
about 317 species; herbs, some of which are introduced into
our gardens and greenhouses. The stems are nodose; the leaves
often _clasping_; the flowers are arranged in unipared scorpioid
cymes, often so that they form a zig-zag series falling in
the median line of the bracts, and after flowering they bend
regularly to the right or left, outwards or inwards. They
are more or less _zygomorphic_, particularly in the stamens,
which in the same flower are of different forms or partially
suppressed. The outer series of the _perianth_ is sepaloid,
the inner petaloid, generally violet or blue; the filaments
are sometimes clothed with hairs formed of rows of bead-like
cells (well known for showing protoplasmic movements). Fruit
a trilocular _capsule_ with loculicidal dehiscence (generally
few-seeded); in some a nut. The radicle is covered by an
external, warty, projecting covering which is cast off on
germination.--The abundant raphides lie in elongated cells whose
transverse walls they perforate.--_Commelina, Tradescantia,
Tinantia, Cyanotis, Dichorisandra_.
Order 2. =Mayacaceæ.= This order is closely allied to the
Commelinaceæ. 7 species. American marsh- or water-plants.
In many of the following orders of this family the flowers are
united into compound inflorescences, with which is accompanied a
reduction in the flower.
Order 3. =Xyridaceæ= (50 species). Marsh-plants with radical,
often equitant leaves arranged in 2 rows, and short spikes on
long (twisted) stalks. The flowers, as in the Commelinaceæ, have
sepals (which however are more chaffy) and petals, but the outer
series of stamens is wanting. Capsule (generally many-seeded).
Order 4. =Rapateaceæ.= Marsh-plants with radical leaves, usually
in two rows, and several spikelets on the summit of the main
axis, clustered into a capitulum or unilateral spike. Each
spikelet has numerous imbricate floral-leaves and one flower. 24
species. South America.
Order 5. =Eriocaulaceæ.= The “Compositæ among Monocotyledons,”
a tropical order. The flowers are borne in a _capitulum_
surrounded by an _involucre_, very similar to that of the
Compositæ. The flowers are very small, unisexual, ♂ and ♀
often mixed indiscriminately in the same capitulum; they have
the usual pentacyclic structure; the leaves of the inner
perianth are often connate and more membranous than the outer;
in some the outer series of stamens are suppressed; in each of
the 3 loculi is one pendulous ovule. Capsule. The leaves are
generally radical and grass-like.--335 species; _Eriocaulon_,
_Paepalanthus_, etc., _E. septangulare_ on the west coast of
Scotland, and Ireland, and in North America.
Order 6. =Restiaceæ.= A small, especially S. African and S.
Australian, xerophilous order (about 235 species), which is
quite similar in habit to the Juncaceæ and Cyperaceæ. The
leaves are often reduced to sheaths. The flowers are diœcious,
the perianth as in _Juncus_, but the outer series of stamens
suppressed. The ovary and fruit as in Eriocaulaceæ; the ovary,
however, may be unilocular, and the fruit a nut. _Restio_, etc.
Order 7. =Centrolepidaceæ.= These are the most reduced plants
in the family; small grass- or rush-like herbs. The flowers
are very small, naked. Stamens 1–2, carpels 1–∞. 32 species.
Australia.--_Centrolepis_ (flowers generally ☿ with 1 stamen and
2–∞ carpels).