ACANTHACEAE
Morphological description
Herbaceous climbers, armed shrubs in Acanthus, Barleria; stem thickened at the nodes. Stipules absent.
Leaves decussate, simple, usually entire, penninerved, usually with linear cystoliths (except Staurogyne) ;
Inflorescence
Periodical mass-flowering (Strobilanthes s.l.). Illustration in PhytoImages: Acanthus
Flowers
Corolla 2- or 4-lobed, the lobes contorted or imbricate in bud; stamens 2 or 4, epipetalous; ovary superior, 2-locular;
Pods
Seeds
Seeds few, usually (except Thunbergia and Staurogyne) on jaculators (retinacula) and forcibly ejected from the characteristic 2-valved capsule.
Different from :Gesneriaceae, Pedaliaceae and Scrophulariaceae have no cystoliths, no jaculator, no swollen nodes, more numerous seeds.
Distribution : The family worldwide, especially in the tropics, mostly in open places, some genera well represented in, or limited to rain forest. In Malesia c. 40 genera,
including: Acanthus (Old World), in Malesia mainly in mangroves; - Graptophyllum (Malesia, Australia, Pacific), lowland rain forest; - Hygrophila (pantropical), mostly wet places, lowland; - Pseuderanthemum (pantropical), lowland and lower montane rain forest; - Strobilanthes (Indo-Malesia), lowland and montane rain forest; - Thunbergia (paleotropics), primary and secondary rain forest.
Notes:
Ornamentals: Graptophyllum, Justicia (Beloperone*), Sanchezia*, Thunbergia. Medicinal plants: Justicia gendarussa, Strobilanthes.
Literature: C.A. Backer & R.C. Bakhuizen van den Brink, Fl. Java 2 (1965) 544-593; R.M. Barker, J. Adel. Bot. Gard. 9 (1986) 1-286 (Australia). - Dr. B. Hansen (AAU) is coordinating the revision of Malesian Acanthaceae.
Spot characters (Van Balgooy): Acanthaceae 16, 59, 63 - Acanthus 12; A. ilicifolius 60 - Barleria 12 - Blepharis 46 - Hallieracantha 47 - Justicia 85 - Ptyssiglottis 47 - Stauranthera 47 - Strobilanthes 2, 15, 47 - Thunbergia 5, 6, 64; T. laurifolia 38.
Illustrations : Fig. 1- 4. Fig. 1. Asystasia gangetica (L.) Anderss. (Acanthaceae). Reproduced from C.A. Backer, Weed Flora of Javanese Sugar-cane fields, Atlas pt 16 (1973) t. 630. 16 Fig. 2. Justicia gendarussa Burm. f. (Acanthaceae). Reproduced from C.A. Backer, Weed Flora of Javanese Sugar-cane fields, Atlas pt 16 (1973) t. 640. 17 Fig. 3. Staurogyne elongata (Blume) O. Ktze (Acanthaceae). Reproduced from J. J. Ochse & R. C. Bakhuizen van den Brink, Vegetables of the Dutch East Indies (1980) fig. 2. 18 Fig. 4. Thunbergia alata Bojer ex Sims (Acanthaceae). Reproduced from C.A. Backer, Weed Flora of Javanese Sugar-cane fields, Atlas pt 16 (1973) t. 609. 19 Fig. 5. Dracaena (Pleomele) angustifolia Roxb. (Agavaceae). Reproduced from J. J. Ochse & R. C. Bakhuizen van den Brink, Vegetables of the Dutch East Indies (1980) fig. 285.