PHANEROGAMS— PROFESSOR BAYLEY BALFOUR. 109 



GAMOPETALJEL 



Order XXXIV. RUBIACE^. 



A vast natural order, represented in Socotra by nine genera. One of these 

 is endemic, and one is a small genus of a limited range in Madagascar and 

 east tropical Africa; four are spread over the warmer regions of the world, 

 one of them having a maximum in temperate regions ; and three are old world 

 genera, two of which are however restricted to the Mediterranean region and 

 Western Asia. 



1. DIRICHLETIA. 



Dirichletia, Klotzscb in Monatsb. Akad. Wiss. Berol. 1853, 494, and in Peters' Mossamb. Bot. 

 tt. 4*7, 48 ; Beuth. et Hook. Gen. PI. ii. 56. 



A small genus, consisting now of seven species, inhabiting east tropical 

 Africa, Madagascar, and Socotra. Four species are found in Socotra, no less 

 than three being endemic, and the fourth is a Somali Land plant. 



The development of this genus in Socotra is exceedingly interesting, and 

 the discovery of our specimens enables us to complete the generic description 

 in Bentham and Hooker's Genera Plantarum, and also necessitates slight 

 emendation of the generic characters. In the only species of which we have 

 flowers these are dimorphic, and possibly this is characteristic of the whole 

 genus. The calyx limb is dilated into a wing, sometimes 5-lobed ; the lobes of 

 the corolla and the stamens are often five. The disk is often quite glabrous, 

 and the style is often-four cleft. The testa is very tough and the albumen 

 may be fleshy. The following, then, is the amended generic character : — 



Calycis tubus parvus, obconicus ; limbus in laminam arnplissimam reticulatum concavam 

 obliquam late unilabiatam v. 4-5-lobatain excrescens, membranaceus, persistens. Corolla 

 infundibularis v. tubulosa, tubo gracili elongato fauceque intus glabro v. piloso ; limbi 

 lobi 4-5, breves, triangulares, reduplicatim valvati. Stamina 4-5, infra faucem corolke 

 inserta, filamentis filiformibus ; antberaa inclusae, dorso affixse, liueari-oblongae, utrinque 

 obtusae. Discus tumidus glaber v. pubescens. Ovarium 2-loculare ; stylus filiformis 

 inclusus ramis 2-4 undique papillosis ; ovula in loculis pauca, ad apicem placentae carnosse 

 columnaris a basi loculi adscendentis sessilia. Fructus coriaceus irregulariter debiscens, 

 oblongus, incurvus, 2-locularis, loculis 1-spermis. Semina erecta, oblonga, obtusa, testa 

 coriacea, albumine corneo v. carnoso ; cotyledones foliaceae ; radicula cylindrica. — Suffrut- 

 ices ramosi, ramulis 4-gonis, pubescentes v. tomentosi. Folia opposita, petiolata mem- 

 branacea, ovato-lanceolata, nervosa, nervis obliquis. Stipulae 3-cuspidatae v. 3-5-setosae. 

 Flores dimorphici in cyrms terminale= corymbosas dispositi. 



