ACANTHACE.E. 451 



— Leaves opposite, exstipulate, usually entire or crenulate-repand : the pair often unequal : 

 herbaceous parts usually lineolate (by adnate down) j flowers usually supported by brac- 

 teoles ; seeds mostly compressed. 



This Order is mucilaginous ; it affords slightly bitter or aromatic drugs (Dianthera). 

 Fixed oil is extracted from the seeds of Sesamum : this genus, though anomalous, approaches 

 Acanthaceee by Thunberyia. 



Tribe I. ECHMATACANTIIEM, Ns.— Dissepiment of the capsule 2-partite. Seed* 

 supported by retinacula (except in Elytraria). 



Series 1. Ruellidese, T. A nders. MS. — Corolla-lobes sinistrorsely contorted. Filaments 

 connected in pairs at the base. 



1, ELYTRARIA, V. 



Calyx 5-4-partite, unequal. Corolla small, 2-lipped. Fertile stamens 2 : anther-cells 

 parallel. Capsule 8-seeded : segments of the dissepiment adnate to the valves : retinacula 

 none. — Herbs ; superior leaves transformed into decussate, appressed scales, inferior rosulate; 

 flowers spicule ; bracts and bracteoles scarious. 



1. E. tridentata, V. Annual; rosulate leaves lanceolate-oblong, scales subulate-lanceo- 

 late ; bracts subulate, ciliate, awned, superior often emarginate. — E. frondosa, fasciculata, 

 and ratnosa, Kth. E. apargiifolia, Ns. — Variable in the scaly branches all from the base 

 or axillary, the down, the sphkes simple or ternate, the bracts acuminate or awned from the 

 emarginate top. — Hab. Trinidad !, Lockh., on rocky soil ; [New Mexico ! to Buenos Ayres !]. 



2. RUELLIA, L. 



(Dipteracanthus and Cryphiacanthus, Ns.) 



Calyx 5-partite or deeply 5-fid, subequal. Corolla infundibular : limb subequal. Stamens 

 didynamous, included : anther-cells parallel. Capsule 4 -24 (-2) -seeded : segments of the 

 dissepiment adnate to the valves, often at length reduced above the seeds. — Herbs or shrubs ; 

 flowers axillary, racemose, or in axillary cymes. 



Sect. 1. Gymnacanthus, Oerst. Calyx deeply 5-fd. Capsule not compressed, ^-%-seeded 

 above the solid base -. retinacula denticulate at the summit. Flowers axillary, sessile, 

 ebracteolate. 



2. R. geminiflora, Kth. Herbaceous or suffrutescent, hairy or glabrescent; leaves 

 lanceolate, lanceolate-oblong, or ovate, subsessile ; flowers 2-1 in the axil ; calyx<-segments 

 linear-acuminate ; corolla-tube enlarged from the middle ; capsule ovoid, pubescent, 4-seeded 

 above the base. — Dipteracanthus, Ns. ! — Usually l'-2' high ; calyx 4"'-5"', purple corolla 

 1"-1£" long. 



[a. Down spreading; leaves ovate-oblong or oblong, l"-li" long.] 



/3. angustifolia. Down spreading ; leaves lanceolate, lj"-2i" long. — D. geminiflorus, 

 var. angustifolius, Ns. ! 



y. canescens. Down pubescent, short ; leaves oblong-lanceolate, I" long. — Dipteracan- 

 thus canescens, Ns. I 



Hab. Jamaica !, Macf, Pd., Wils., March, in savannahs (y) ; Trinidad !, Lockh., Cr. (fi) ; 

 [Cuba ! aud Mexico ! to Peru I and Brazil !]. 



Sect. 2. Aphragmia, Ns. — Calyx deeply h-partite. Capsule subcompressed, 16-4(-2)- 

 seeded: retinacula subulate. — Cymes spreading, axillary: 2 bracts below the lateral 

 flowers. 



3. K. panicnlata, L. Shrubby, glandular ; leaves ovate-lanceolate, cuneate at the 

 ne'tioled base ; cymes in a divaricate panicle ; calyx-segments linear-Aliform : bracts lanceo- 

 late • corolla-tube enlarged above the middle ; capsule oblong-linear, laterally subcompressed, 

 8-12-seeded above the base: seeds smooth.— SI. t. 100./. 2.— Dipteracanthus, Ns. !— 2'- 

 8' high, trailing ; calyx 4'", blue corolla 1" long.— Hab. Jamaica !, Macf, March, in dry 

 ned-'es of the southern hills ; [Mexico to Venezuela], 



