1952] 



PLANTS COLLECTED IN ECUADOR 



57 



(sensu vero, non sensu A. C. Smith, Contr. U. S. Nat. Herb. 28: 335-348. 1932) 

 was pointed out by Sleumer (Notizbl. Bot. Gart. Berlin 12: 278-282. 1935) and my- 

 self (Bull. Torrey Club 63: 307-309. 1936). Periclesia was established by the 

 writer on the basis of a single species. At that time the distinction between the 

 two genera seemed adequate, Periclesia having 4-merous flowers with extremely 

 large calyx-lobes and connate filaments. 



Now, however, several additional species have been referred to Ceratcstema 

 and four additional ones to Periclesia. These species serve effectively to break 

 down the differences originally believed to separate the two genera, and the exten- 

 sive material of this complex assembled by Dr. Camp and his assistants further 

 indicates that the two concepts are no longer useful. With the addition of three 

 novelties herewith described, 16 species of Ceratostema (sensu vero) may now be 

 recognized. In order to facilitate identification in this difficult genus I give below 

 a key to the known species. 



Ceratostema may be circumscribed as having the following fundamental char- 

 acters: calyx articulate with pedicel (the articulation rarely obscure or even 

 lacking, in C. loranthiflorum); corolla large, often ventricose near base, deeply 

 lobed; filaments free or connate, glabrous or pilose (but never with massed retrorse 

 hairs); stamens with strongly granular thecae and very slender stiff tubules which 

 dehisce by short oblique subterminal pores. It is geographically limited to the 

 Andean area extending from southern Colombia through Ecuador and possibly into 

 northern Peru, the precise locality of some collections being questionable. In the 

 Ecuadorian Andes Ceratostema seems to be one of the most frequent and certainly 

 one of the most striking vacciniaceous constituents of the flora. 



In reconsidering the genus Ceratostema mention should be made of C. speciosum 

 Andre (Illustr. Hort. 17: 52. pi. 9. 1870; A. C. Smith, Contr. U. S. Nat. Herb. 28: 

 345. 1932), which I referred to the genus Plutarchia in 1936 (Bull. Torrey Club 

 63: 312). The type of the species was obtained near Loja (south of the usual range 

 of Plutarchia), and from the inadequate original description and plate it seems 

 possible that the species actually does represent Ceratostema in the sense of the 

 present treatment. The important character of the anther-dehiscence cannot be 

 ascertained from the original publication; lacking this, I am still unable to place 

 the species with certainty. If it does fall into Ceratostema it appears distinct 

 from any of the species in my key below. 



KEY TO THE SPECIES OF CERATOSTEMA 

 Calyx-limb very conspicuous, the lobes elongate-deltoid, at anthesis at least 

 10 mm. long. 



Leaf-blades deeply cordate at base; calyx-lobes membranaceous, conspic- 

 uously reticulate-nerved. 

 Rachis, pedicels, and calyx pilose with whitish eglandular hairs} bracts 

 and bracteoles small; calyx-tube 10-costate; leaf-blades soft-pilose 

 beneath. C. peruvianum Gmel. 



Rachis, pedicels, and calyx copiously pilose with weak gland-tipped 

 hairs; bracts and bracteoles papyraceous, 5—17 mm. long; calyx- 

 tube terete; leaf-blades essentially glabrous. 



C. pensile A. C. Smith, comb. nov. 



Leaf-blades attenuate to obtuse at base. 



Calyx-tube obconical, smooth, the lobes membranaceous, conspicuously 

 reticulate-nerved; anthers with thecae 5-6 mm. long; flowers 4- 

 merous; leaf-blades 4-6 XL2-1.8 cm. 



C. flexuosum (A. C. Smith) Macbr. 

 Calyx-tube costate or winged, the lobes chartaceous to coriaceous; an- 

 thers with thecae 8-18 mm. long; flowers 5-merous (calyx- and 

 corolla-lobes sometimes partially fused). 



