348 MR. G. BIKTHAM OJT OECniDE^!. 



rostellum or at a distance from it. The rhizome is generally more 

 or less tuberiferous, producing simple erect flowering-stems, 

 either leafless or with a single leaf, the leaves usually arising 

 separately from the rhizome or sometimes entirely wanting : it is 

 only in a few species of Pogonia that the flowering-stem bears two 

 to four leaves ; the raceme or spike is always simple and terminal. 

 The geographical distribution is extensive, a considerable propor- 

 tion of the species being dispersed over the temperate regions of 

 the northern hemisphere, some with a wide specific area; some 

 also are tropical, either in the New or the Old World ; beyond the 

 tropics in the southern hemisphere they are very rare, only two 

 species being known in extratropical Australia and one in extra- 

 tropical South America, none in South Africa. 



The eight following genera are the only ones we would include 

 in the subtribe. Arethusa, Linn., has three species, one from 

 Japan and one from North America, to which we would add as a 

 third the Cryle, Lindl., from Guatemala, which, with precisely 

 the same floral structure, differs in the tardy development of two 

 or three leaves from a bud of the rhizome separate from the 

 flowering scape. Calopogon, B. Br., contains three or four closely 

 allied species from North America and the "West Indies, Wright's 

 no. 3317, from Cuba, being but slightly distinct from the common 

 O. pulclellus. Pogonia, Juss., as extended by Blume and by 

 Eeichenbach, comprises about thirty species, closely connected in 

 their floral structure, but capable of being distributed into five 

 sections, so well marked out by vegetative characters as to have 

 been plausibly regarded by some as so many distinct genera. 

 These are: — 1. JSfervilia, Gaudieh., including Cordyla, afterwards 

 Rophostemon, Blume, and Aplostellis, Thou., about fifteen tropical 

 or subtropical Old-World species ; 2. Pogonia proper, two North- 

 American species, of which one is also in Japan ; 3. Cleistes, L. 

 C. Eich., of which eleven species have been published, but several 

 of them not really distinct, all from tropical America; 4. Tri- 

 phora, Nutt., about eight American species, northern or tropical ; 

 5. CodonorcJris, Lindl., two American extratropical species, one 

 northern, the other southern. Chlorosa, Blume, a single Javau 

 species, is only known to me from the author's figure and descrip- 

 tion ; he compares it with Cryptostegia, but the characters given 

 appear to me to bring it much nearer to Pogonia. Leucorchis, 

 Blume, two or three species from the Indo- Australian and South - 

 Pacific regions, includes Apetalon, Wight, and Epiphanes,Heichb. f. 



