24 NORTH AMERICAN FLORA [VOLUME 32 
flexed after dehiscence. Seeds crateriform, peltate, nearly smooth; endosperm corneous; 
embryo minute, clavate. 
Type species, Peplis tetrandra L,. 
1. Clavenna tetrandra (L.) Standley. 
Peplis tetrandra L,. Amoen. Acad. 5: 413. 1760. 
Hedyotis tuberosa Sw. Obs. 136. 1791. 
Oldenlandia tuberosa Lam. Encyc. 4: 535. 1797. 
Lucya tuberosa DC. Prodr. 4: 434. 1830. 
Lucya tetrandra K. Schumann, in E. & P. Nat. Pfl. 44: 27. 1891. 
Dunalia tetrandra Kuntze, Rev. Gen. 281. 1891. 
Stems few or numerous, 5-15 cm. long, simple or sparsely branched, striate-angulate, 
minutely scaberulous or glabrate, the internodes short or elongate; stipules 0.5 mm. long or 
shorter; petioles slender, 1-4 mm. long; leaf-blades ovate to rounded-ovate, oval, or elliptic, 
5-15 mm. long, 2—9 mm. wide, broadly rounded to acute at the base, usually abruptly decurrent, 
acute to very obtuse at the apex, thin, bright-green, slightly paler beneath, sparsely hispidulous 
on both surfaces or glabrate, 3- or 5-nerved, the lateral nerves often obsolete; pedicels filiform, 
deflexed or spreading after anthesis, 6 mm. long or shorter; hypanthium and calyx at anthesis 
1.5 mm. long, densely hispidulous; corolla equaling or slightly exceeding the calyx-teeth; capsule 
2.5 mm. long, 3.5—4 mm. broad; seeds oval, 1.5 mm. long, black. 
TYPE LOCALITY: Jamaica. 
DISTRIBUTION: In crevices of moist cliffs, Greater Antilles. 
ILLUSTRATIONS: Sw. Obs. pl. 1, f. 2; Jacq. Sel. Stirp. Am. pl. 180, f. 29. 
13. HOUSTONIA 1. Sp. Pl. 101. 1753: 
Poiretia J. F. Gmel. Syst. 2: 263. 1791. 
Panetos Raf. Ann. Gén. Sci. Phys. 5: 227. 1820. 
Chamisme Raf.; Steud. Nom. Bot. ed. 2. 1: 776, as synonym. 1840. 
Stenaria Raf.; Steud. Nom. Bot. ed. 2.1: 776. 1840. 
Erect or prostrate herbs or rarely low shrubs, glabrous or pubescent. Leaves opposite, 
sometimes with fascicles of leaves in their axils, sessile or petiolate, the blades broad or narrow. 
Stipules entire, dentate, or laciniate, persistent. Flowers often dimorphous, white, purple, or 
blue, axillary or in dichotomous cymes, the pedicels erect or recurved in fruit; hypanthium 
terete or compressed, globose, oblong, or turbinate; calyx-lobes 4, sometimes with interposed 
glands, remote, erect or recurved; corolla funnelform or salverform, the tube short or 
elongate, glabrous or pilose within, the lobes 4, valvate, glabrous or pilose within. Stamens 4, 
inserted in the throat of the corolla; filaments short or elongate; anthers dorsifixed, oblong or 
linear. Disk inconspicuous. Ovary 2-celled; style slender, the branches 2, linear; ovules few or 
numerous, the placentae attached by the middle to the septum. Capsule one fourth to three 
fourths superior, few- or many-seeded, loculicidally dehiscent. Seeds crateriform to concavo- 
convex, peltate, the ventral face concave; endosperm corneous; embryo clavate. 
Type species, Houstonia caerulea L. 
Pedicels recurved in fruit. 
Leaf-blades mostly suborbicular; plants prostrate, perennial, with root- 
stocks or with slender branches rooting at the nodes. 1. H. procumbens. 
Leaf-blades linear or oblong-linear; plants mostly erect or ascending, or, 
if prostrate, annual. 
Plants perennial. 
Corolla 15—25 mm. long. 
Corolla 2.5—-4 mm. long. 
Plants annual. 
Corolla 6—7 mm. long; calyx-lobes 3-4 mm. long. 4. H. humifusa. 
Corolla 2-3 mm, long; calyx-lobes 2 mm. long or shorter. 
Hypanthium glabrous, minutely papillose; pedicels shorter 
than the capsules. 5. H. prostrata. 
Hypanthium hirsutulous. 
Pedicels equaling or longer than the capsules; plants erect. 6. H. subviscosa 
Pedicels shorter than the capsules; plants procumbent. 7. H. Croftiae. 
Pedicels erect or ascending in fruit. 
Plants annual. 
Corolla searcely exceeding the calyx-lobes. 8. H. parviflora. 
Corolla 4—9 mm. long, much exceeding the calyx-lobes. 
Capsule as long as broad or longer; leaf-blades linear or nearly so. 
Flowers mostly sessile; capsule subglobose. 9. H. arenaria. 
. rubra. 
. Wrightii. 
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