FLORA OAPENSIS. 
Orver Cl. ACANTHACEZ. 
(By C. B. Crarxz.) 
Flowers hermaphrodite, irregular. Calyx inferior, free ; segments 
5 or 4, nearly separate or united. Corolla gamopetalous; tube 
campanulate or linear ; limb 2-lipped or 5-lobed, more or less 1-sided. 
Stamens on the corolla, 4 didynamous, or. 2 (with or without 
rudiments of others) ; anther-cells 2 or 1, rounded acute or tailed 
at the base, parallel at equal height, or one more or less below the 
other ; pollen ellipsoid (then usually ribbed or banded longitudinally) 
or globose (then often honeycombed or echinulate) ; equatorial pores 
2 or 3 (for the protusion of pollen-tubes) closed by stopples. Ovary 
superior, 2-celled; ovules 2 or several in each cell, superimposed, or 
sometimes the lower ovule in each cell rudimentary or wanting, or 
(in Thunbergia) 2 ovules, collateral in each cell ; style long, simple, 
minutely 2-fid. Capsule loculicidal, often elastically dehiscent ; 
in a few genera the placentw, remaining attached to the top of the 
capsule, spring up elastically from the bottom, thus scattering the 
seeds. Seeds usually as many as the ovules (except in several genera 
where the lower ovule in each cell is imperfect), held up on the 
thickened upcurved outgrowth of the funiele (the retinaculum), 
except in Thunbergia. 
Herbs or shrubs. Leaves opposite, nearly always simple, entire ; stipules 0. 
Inflorescence very various (even in the same genus), in strobilate spikes, or in 
heads or clusters, or of remote solitary flowers. Bracts large, or small or 0; 
bracteoles 2 (prophylla) often present, large or small. 
Species 2000, abundant in the Tropics, frequent in temperate climates, absent 
in cold regions, in Europe only represented by 8 or 4 species of the genus Acanthus 
which reach the Mediterranean, 
The Order is marked (except Thunbergia) by the strong upcurved hooks which 
carry the seeds ; cf. Dyer, Fl. Trop. Afr. vy. 1, 2. 
Tribe 1, THUNBERGIEZ. Corolla not, or obscurely, 2-lipped ; lobes con- 
torted in the bud, i.e. no lobe wholly within or without the others, Ovules 2 in 
each cell, collateral. Capsule beaked. Seeds orbicular, without retinacula. 
I, Thunbergia.—Bracteoles 2, large, enclosing the small calyx. 
Tribe 2. RUELLIEZ. Corolla lobes contorted in the bud. Stamens 4, 
or in Chetacanthus 2; anther-cells at nearly equal height. Caly# or 
bracteoles often conspicuous. Seeds discoid, covered, at least on the margins, with 
numerous fine white hairs which spring out on applying water. ; 
Subtribe 1. HyGropnitex. Ovules 3 or more in each cell. Capsule (unless 
accidentally) with more than 4 seeds. Corolla distinctly 2-lipped. 
II. Hygrophila.—Stamens 4; anther-cells muticous ; pollen ellipsoid, ribbed 
longitudinally, 
vO, Y, B 
