RUBIACE^. 259 



adventitious roots i and rough herbaceous aerial branches, opposite 

 leaves and leaflike stipules. The flowers ^ are collected in axillary 

 and terminal compound cymes, and the pedicel is articulate under 

 the ovary. 



The flowers are sometimes tetramerous in Ruhia (fig. 226). It is 

 the rule in Galium,^ the pericarp of which is dry, or coriaceous,* or 

 less fleshy than that of Ruhia proper, though this difference, presenting 

 every possible gradation, can justify only its forming a section of the 

 genus Ruhia (from which Gralium is ordinarily distinguished as a 

 genus). In some American species of Galium the inflorescences are 

 surrounded by an involucre of four bracts; of these a genus, 

 Relhunium,^ has been made. , 



In Mexico there is a Ruhia with fleshy fruit, whose opposite leaves 

 are accompanied with four interfoliar stipules little developed instead 

 of presenting the form and appearance of leaves proper ; the generic 

 name of Didymcea * has been conferred upon it. 



In the Ruhias of the section Galium, the surface of the friiit is 

 sometimes smooth and sometimes charged with asperities, points or 

 tubercles. In one, G. cristatum,'' native of Assyria, each of the cocci 

 has three more distinct prominences in the form of sinuous or dentate 

 crests, the upper teeth of which may also be hooked ; this has 

 ■constituted a genus Mericarpmi.^ 



In some species of Galium, such as G, Cruciata, &c., there are in 

 the axil of the leaves, not one, but two collateral cymes, or three, 

 one medial and two lateraL The number of flowers in each cyme 

 may be inuch reduced.' In some species, of which the genus 

 Vaillantia ^" has been made, there are only three flowers in the axil. 

 The medial is hermaphrodite and tetramerous, and the lateral are 



' The numter of which, we know, is aug- ° Endl. Gen. 523 (sect. Galii). — B. H. Gen. ii. 



mented in cultivation hy earthing up. 149, n. 330. 



* Small, yellowish or pale green. ^ Hook. p. Gen. ii. 150, n. 333 ; Icon. Plant. 



=• T. Imt. 114, t. 39 {Gallium).— Jj. Gen. n. t. 1271. 



125.— Scop. M. Carniol. (ed. 2) i. 94. —DC. ? Jaub. et Spach, J«. P^. Oc. ii. t. 191. 



Prodr. iv. 693.— Rich. £ub. 53.— Spach, Suit, a ' Boiss. Dlagn. Or. iii. 61 ; Fl. Or. "iii. 83.— 



fon, viii. 469.— Endl. Gen. n. 3100.— B. H. B. H. Gen. ii. 149, n. 332. 



Gen. ii. 149, n. 331: — Hook. Fl. Ind. iii. 204. — ' And often, in a few-flowered cyme, the 



Aparine'Y. Inst. 114, t. 39. — Oruciatn'S.lcc.cit, lateral flowers are male, sometimes trimerous, 



115, t. 39. — Fyselia TS'ECS.. Elem, u. 333. — As- the central alone being hermaphrodite. 



pera Mcench, Meth. 640. " T. Act. Acad. Par. (1705) 234.— L. Gen. n. 



^ It may be inflated, more or less vesicular, 1151 (Valantia). — Voib.. Bkt.yiii. 285 (part). — 



as in G. glaucum L. On this character is DC. Fl. Fr. iv. 266 ; Prodr. iv. '613. — Rich. 



founded the genus Mieropkysa (Scheenk, Bull. Rub. 54, t. 1, ig. 2. — Ekdl. Gen. n. 3098. — B. H. 



Acad. Pelersb. ii. 115.— Walp. Rep. vi. 18). Gen. 148, u. 3'38.— H. Bn. Payer Fam. Nat. 232. 



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