CONTRIBUTIONS FROM THE GRAY HERBARIUM OF HARVARD 

 UNIVERSITY, NEW SERIES, No. XI. 



By J. M. Greenman. 



Presented by B. L. Robiason, 14 April, 1897. 



I. — REVISION OF THE MEXICAN AND CENTRAL 

 AMERICAN SPECIES OF HOUSTONIA. 



HOUSTONIA, Gronov. (Named in honor of Dr. William Hous- 

 toun, born in Scotland, 1695, died in Jamaica, 1733.) — Calyx-tube 

 usually a little compressed ; lobes 4, often with one or more minute 

 teeth in each sinus, erect or spreadic^, --»ersistent, later becoming widely 

 separated. Corolla funnelform or salverfbrm, 4-lobed, glabrous or pilose 

 in the throat; lobes valvate. Stamens 4, inserted in the throat of the 

 corolla ; filaments short or elongated ; anthers dorsally affixed, oblong or 

 linear. Disk inconspicuous. Ovary 2-celled ; style terete, slender, 

 short or elongated ; stigmas 2, linear or linear-oblong ; ovules in each 

 cell few or many, centrally attached to the median placenta. Capsule 

 ^ to f inferior, more or less subglobose, obovate, obovate-oblong, or 

 turbinate ; seeds crateriform, acetabuliform, or oblong, peltate and 

 slightly concave on the hilar surface, usually scrobiculate ; albumen 

 horny ; embryo clavate. — Gronov. in L. Syst. Nat. ed. 1 ; L. Gen. 

 no. 70; Benth. & Hook. f. Gen. ii. 60; Gray, Syn. Fl. N. A. i. pt. 2, 

 24 ; Schumann in Engl. & Prantl, Nat. Pflanzenf. iv. Ab. 4, 27. Poire- 

 tia, Gmel. Syst. 263. Panetos, Raf. Ann. Gen. Sci. Phys. v. 227, vi. 81. 

 Chamisma, Raf. in Steud. Nom. ed. 2, i. 776, in syn. — Low slender 

 annuals, herbaceous perennials, or suflfruticose plants with reciprocally 

 dimorphous flowers. 



§ 1. EuHOusTONiE^. Low herbaccous plants often much branched 

 from a woody perennial base : leaves ovate, oblong, linear or subterete, 

 not rigid-setaceous nor acerose-linear : capsule globose, obovate, or obloug- 

 obovate, more or less compressed and usually emarginate : seeds cra- 

 teriform, acetabuliform, or oblong, peltate and slightly concave on the 

 hilar surface, scrobiculate. — Gray, Proc. Am. Acad. iv. 313. 



