General description:- Herbs or shrubs.
Leaves:-
1) Simple, opposite, without exstipulate.
Flowers:-
1) Zygomorphic.
2) Inflorescences, spike-like.
3) Bracts, often conspicuous, coloured.
4) Calyx, 4-lobed, 2-lipped, or campanulate. 5-fid.
5) Corolla,
a) petals, sympetalous, zygomorphic, with a short tube;
b) limb, 2-lipped with the upper lip subentire and the lower 3-petalled or 1-lipped
with the upper lip absent.
6) Stamens, 2 or 4.
7) Ovary, superior, 2-locular, with axile placentae.
a) style, single, unequally 2-lobed.
Fruit:-
1) Capsule, loculicidal, with an indurated funicle and jaculators
ACANTHUS
General description:- Robust perennial herbs or small shrubs.
Stems:-
1) Simple, terete, erect.
Leaves:-
1) Mostly basal, lobed, the
a) lobes pinnatifid or pinnatisect
Flowers:-
1) In dense, terminal, cylindrical spikes.
2) Bracts, large, spinose-dentate.
a) bracteoles, entire, lanceolate to linear.
3) Calyx, 4-lobed;
a) lobes, upper and lower, large, the
b) lateral, small.
4) Corolla, 1-lipped (upper lip absent), 3-lobed;
b) tube, short.
5) Stamens, 4, included;
a) anthers 1-celled, connate in pairs.
Fruit:- A capsule.
Key features:-
1) Basal leaves, pinnatifid to pinnatisect.
2) Corolla, 1-lipped.