Englerodoxa Hoer. Bot. Jahrb. 42: 310. 1909.
Periclesia A. C. Smith, Contr. U. S. Nat. Herb. 28: 357. 1932.
In my treatment of 1932 I recognized the genus Englerodoxa as composed of three species; shortly afterward the identity of this concept with Ceratostema (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 myself (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 Ceratostema and four additional ones to Periclesia. These species serve effectively to break down the differences originallybelieved to separate the two genera, and the extensive 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 characters: 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.