ORCHIDACEM 11 



ILLUSTRATIONS OF THE GENUS 

 DENDROCHILUM 



The genus Dendrochilum as at present understood through 

 the recent monograph by J. J. Smith includes the genera Platy- 

 clinis founded by Bentham on Blume's second section of Den- 

 drochilum, and Acoridium based on an imperfectly known plant 

 which Nees & Meyen referred to the Philydracese. Platyclinis 

 was characterized by the terminal, Dendrochilum by the lateral 

 origin of the inflorescence. Until recently Acoridium has been 

 interpreted through two or three species, all of which have been 

 also variously treated as Dendrochilum or Platyclinis, although 

 clearly marked by having the inflorescence terminal and the column 

 wingless. The species of characteristic Dendrochilum, that is, 

 plants with lateral flower shoots, are at present in the minority, 

 while the species assigned by authors to Platyclinis and Acoridium 

 form the bulk of the genus. This fact probably indicates that the 

 lateral inflorescence is anomalous in Dendrochilum, as it is in some 

 other genera; as, for example, in Epidendrum, where E. Stamfor- 

 dianum is exceptional in this respect. 



Since the explorations of the Philippine Islands were under- 

 taken by the American Government, many additions have been 

 made to the genus which are of great importance in view of its 

 heretofore unsettled condition. These additions have been for the 

 most part of the nature of Acoridium, agreeing with A. tenel- 

 lum, Nees & Meyen, in the structure of the column, which is 

 devoid of lateral arms, or wings. Altogether they form a fairly 

 complete transition between A. tenellum and Dendrochilum 

 palawanense, and prove conclusively, it seems to me, that Acori- 

 dium should include Bentham's Platyclinis. Furthermore, they 

 clearly show that the generic limits may properly be widened to 

 include not only such habitally very dissimilar forms as A. tenel- 

 lum and P. Cobbiana, but also D. aurantiacum and its allies. 



