RHAMNAOE^. 



63 



Colletia cruciata. 



is one ovule inserted at the base of the internal angle, with micro- 

 pyle ascending and at first directed downwards and inwards but, 

 as in Rhamnus^ ultimately becoming more or less decidedly lateral.^ 

 The fruit, accompanied at the base by a receptacular cupule,^ is a 

 drupe, with thin mesocarp, finally dry, and formed of three cocci 

 which separate and open in two valves to 

 liberate each an albuminous seed, analogous 

 to that of the Buckthorns, plano-convex, with 

 a crustaceous testa. Colletia consists of shrubs 

 from the temperate and cool regions (espe- 

 cially the western) of South America, often 

 leafless or with very small leaves decussate, as 

 also the axillary branches, often thickened, 

 spinescent, vertically flattened and generally 

 nearly triangular.^ The flowers, axillary and 

 solitary, or collected in few- flowered cymes, 

 are situated under these axillary branches. 

 A dozen species* are known. Formerly the 

 genus included a much larger number ; but it 

 has recently been dismembered of a number of secondary genera 

 which in other respects scarcely possessed the value of a section. 

 Sometimes it happens that, the fruit separating into cocci as in 

 Colletia^ the disk is attached in the form of a cupule to the bottom of 

 the perianth, and that the opposite and spinous branches are articu- 

 late, as in Discaria, natives of South America, New Zealand, and 

 Australia ; or the floral receptacle, less deep and ob conical, its 

 concavity lined with the disk, supports an open perianth with 

 independent folioles, as in Adolphia infesta^ a subaphyllous 

 American shrub, with opposite and articulate spinous branches. 

 In Retanilla^ Chilian and Peruvian shrubs, spinous and leafless, the 

 diminishing disk ascends the internal surface of the perianth, and 

 the fruit is a drupe with a 1-3 -celled putamen. The same fruit is 

 observed in Talguenea and Trevoa, also from South America, but 



Fig. 57. Long. sect, of 

 flower (A). 



^ A double envelope. 



2 After floration, the perianth often detaches 

 itself circularly above the interior projection of 

 the disk and falls with the androecium. 



^ At least looked at in profile. 



'' H. B. K. Nov. Gen. et Spec. vii. 59.— Spreng. 



Syst. i. 825 (Cow^c/ia).— Hook, and Gill. Bot. 

 Misc. i. 151, t. 43,44; iii. 172.— Vent. Jard. 

 Cels. t. 92— LiNDL. Joum. Sort. Soc. v. 29, Ic— 

 C. Gay, Fl, Chil. ii. 28 (part.).— A. Gray, Amer. 

 Expl. Exp. Bot. i. 276. — Wedd. Ghl. Andin. ii. 

 183.— Bo^ Mig. t. 5033.— Walp. Ann. vii. 603. 



