220 
ACANTHACEAE 
to become monochasial, and frequently condensed in the leaf- axils as 
in Labiatae. Racemose infls. also occur. Bracts and bracteoles 
usually present, often coloured ; the latter frequently large, more or 
less enclosing the fir. 
Fir. $ , hypogynous, zygomorphic, usually with a nectariferous 
disc below the ovary. K (4 — 5), C (4 — 5), commonly two-lipped 
(the upper lip sometimes not developed, eg. in Acanthus). Sta. 
rarely 5, usually 4 or 2 epipetalous ; staminodes frequently represent 
the rest of the whorl ; anthers often with one lobe smaller than the 
other, or abortive ; connective often long (cf. Salvia). The pollen 
exhibits a great variety of patterns (see Nat. PJl .). G (2), 2-loc. 
with axile placentae each with 2 — 00 usually anatropous ovules in two 
rows. Style usually long with two stigmas. The general arrangement 
of the fir. for visits of insects, protection of pollen, &c. is like that of 
Labiatae or Scrophulariaceae. 
Frt. a bi-locular capsule (with few exceptions), usually more or 
less stalked, and loculicidal to the very base. Seeds usually exalbu- 
minous. Their modes of distribution are interesting (see Nat . PJl.). 
The capsules of Acanthoideae explode and the seeds are thrown out, 
largely by the aid of peculiar hook-like outgrowths from their stalks 
( retinacula or jaculators). Many have superficial scales and hairs 
which on wetting become mucilaginous and may thus aid in animal- 
distribution or in anchorage of the seed to its place of germination 
(cf. Linum, Collomia), e.g. Crossandra, Ruellia, Blepharis. 
Classification and chief genera (after Lindau) : 
I. NELSONIOIDEA E (Ovules 00 ; jaculators papilla-shaped) : 
Nelsonia. 
II. MEND 0 NCI 01 DEAE (Ov. 4, seeds not more than 2. 
Drupe ; no jac.) : Mendoncia. 
III. THUNBERGIOIDEAE (Ov. 4. Capsule; jac. papilla- 
like) : Thunbergia. 
IV. A CANTHIOIDEAE (Ov. 2—00. Capsule ; jac. hook- 
shaped) : 
A. Contortae (cor. convolute, or never ascendingly imbri- 
cate) : Strobilanthes, Ruellia, Eranthemum, Barleria. 
B. I?nbricatae (cor. ascendingly imbricate, or with no upper 
lip) : Blepharis, Acanthus, Crossandra, Aphelandra, 
Justicia. 
Acanthocarpus Lehm. Liliaceae (in). (Tuncaceae Benth. -Hooker). 
3 sp. S.W. Austr. 
Acantholepis Less. Compositae (xi). 1 sp. W. As. 
Acantholimon Boiss. Plumbaginaceae. 80 sp. Orient. Mostly desert 
plants with spiny leaves (see p. 167). 
Acanthomintha A. Gray. Labiatae (vi. 5). 2 sp. Calif. 
Acanthopanax Miq. Araliaceae. 6 sp. Ind., Chi., Japan. 
Acanthophippium Blume. Orchidaceae (15). 4 sp. Indo-Mal. The 
axial outgrowth from the base of the column, common in O., is here 
