ACANTHACE^. (ACANTHUS FAMILY.) 303 



2. DIPTERACANTHXJS, Nees. 



Calyx 2-bracted, 5-partetl, with linear or bristle-like lobes. Corolla funnel- 

 shaped, 5-lobed ; the lobes equal, rounded. Stamens 4, didynamous, included : 

 anthers sagittate. Style simple, or 2-cleft at the apex. Capsule narrowed 

 below the middle, flattened contrary to the partition, 4-12-seeded. Seeds borne 

 above the middle, supported by curved appendages of the placentiE. — Perennial 

 herbs, with tumid joints, entire opposite leaves, and axillary solitary or clustered 

 nearly sessile flowers. Corolla white, blue, or purple. 



§ 1. Calophanes. — Anther-cells pointed at the base: style simple: capsule 



■i-seeded. 



1. D. Oblongifolius. Pubescent and somewhat hoary; stem 4-angled, 

 erect from a creeping base, simple or sparingly branched ; leaves nearly sessile, 

 oval or obovate, obtuse, the upper ones narrower and often acute ; flowers soli- 

 tary or 2-3 in a cluster; calyx-lobes subulate-setaceous, as long as the oblong 

 bracts, and tube of the spotted purple corolla. (Ruellia oblongifolia, Michx.) — 

 Dry sandy pine barrens, Florida to South Carolina, and westward. June - 

 August. — Stem 6'- 12' high. Leaves ^'-V long. Corolla 1' long, rather 

 exceeding the leaves. 



2. D. riparius, n. sp. Stem minutely pubescent, erect from a creeping 

 base, simple, slender ; leaves smooth, membranaceous, oblong, obtuse, slightly 

 crenate, tapering into a long and slender petiole ; flowers clustered, sessile ; 

 calyx-lobes subulate-setaceous, shorter than the spatulate-oblong bracts ; corolla 

 white, 3-4 times shorter than the leaves. — Shady banks of Little River, Middle 

 Florida June and July. — Stems lO-l^o Iiigh. Leaves I'-lj' long. Co- 

 rolla ^' long. 



3. D. humistratUS. Stem smooth, diffuse, creeping; leaves oblong-oval, 

 entire, narrowed into a petiole ; flowers nearly sessile, solitar}- or 2-3 in a clus- 

 ter ; bracts oblong-spatulatc, shorter than the setaceous calyx-lobes ; capsule 

 lanceolate, smooth. (Ruellia Immistrata, Mc/ia:.) — Grassy places, Florida to 

 South Carolina. — Plant small. Leaves ^' long. 



4. D. linearis, Torr. & Gray. Small, rough-pubescent ; stem prostrate, 

 diff"use, very leafy ; leaves oblong-linear, entire, narrowed toward the base, ob- 

 tuse ; calyx-lobes setaceous, hairy ; bracts similar to the leaves ; capsule oblong, 

 4-angled, at length 4-valved, 2-4-seeded. — South Florida. — Stem 6' long. 

 Leaves 4" -6" long. 



§ 2. DiPTERACAXTUUS. — Antker-cells pointkss : sti/le 2-cleJl at the apex : capsule 



8~\2-seeded. 



5. D. ciliosus, Xees. Hirsute with white hairs ; leaves oval or ovate- 

 oblong, nearly sessile ; flowers solitary or 2 - 3 in a cluster ; tube of the corolla 

 twice as long as the setaceous calyx-lobes, and much longer than the short 

 funnel-shaped throat; capsule smooth. (Ruellia ciliosa and R. hybrida, Pursh.) 

 — Dry soil, Georgia, near Savannah, Pursh., and westward. July and Aug. — 

 Stem varying from a few inches to 3° high. Leaves l'-2' long. Corolla 2' 

 long, pale blue. 



