482 Mr. J. Miers on the Tribe Colletiere. 



LIII. — On the Tribe Colletiesej with some Obsei^vations 07i the 

 Structure of the Seed in the Family of the Rhamnacese. By 

 John Miers, E.R.S., F.L.S. &c. 



[Continued from p. 381.] 



Division 3. Clitlirocai'pae. Flores petaliferi; fructus nucamen- 

 taceus et lignosus aut membrauaceus, fere semper indehis- 

 eeiis. 



6. Retamili.4. 



This genus is very distinct from all others of this tribe, dif- 

 fering in its peculiar virgate habit, its almost aphyllous Ephedra- 

 like erect branches ; the reduction of its disk to the size of a mere 

 torus, or stipitate support of the ovary ; and its large, spherical, 

 thick, nuciform fruit. The name of Retanilla was first applied 

 (in 1825) by DeCandolle, in his Prodromus (ii. 28), to a section 

 of the genus Colletia, under which he arranged two plants, di- 

 stinguished from others of that genus by the presence of petals 

 and the absence of the conspicuous disk : these were the Rham- 

 nus Retamilla and Rhamnus IL^^hedra of Dombey, both collected 

 by him in Chile, — Ventenat having previously described both 

 plants as species of Colletia. Brongniart (in 1827) adopted the 

 suggestion of DeCandolle, in his Monograph of the Rhaninacea, 

 and established the genus Retanilla for the same plants, making 

 the type of his genus the Colletia obcordata, Vent, (identical 

 with Rhamnus Retamilla, Domb.). 



There has been an error, originating with DeCandolle (Prodr. 

 ii. 28), in converting Dombey's Spanish name, Retamilla, into 

 Retanilla, the former being the diminutive of Retama, or com- 

 mon Broom of Europe, which resembles the Chilean plant in its 

 almost leafless virgate stems ; but, as the Spanish // has inva- 

 riably a liquid pronunciation, it is desirable to correct the spell- 

 ing in harmony with it, and thus Retamilia becomes the more 

 appropriate name. One of the peculiarities of the genus con- 

 sists in the structure of its fruit, which is much larger than in 

 any other genus of the tribe, is somewhat drupaceous, with a 

 fleshy epicarp that becomes coriaceous, and incloses a hard, 

 ligneous, indehiscent nut, the partitions between its cells being 

 very tliick and woody ; it is smooth, with three slight furrows, 

 corresponding with the lines of the dissepiments ; the trans- 

 verse disposition of the woody fibres of the thick endocarp ap- 

 pears a constant character, worthy of notice. As previously 

 mentioned, Brongniart quotes this as one of the few genera of the 

 Rhamnaceo! in which stipules are wanting ; but in all the sj)eci- 

 mens I have seen they are certainly developed in the manner 

 pcciihar to most of the Collctiece. The generic character is 

 emended in the following manner : — 



