170 ORCHIDALES. fEwDOGBHS. 



Alliance XIII. ORCHIDALES.-— Tuv Orchidal Alliance. 



Diagnosis. — Epigyrums Endogens, with 1 to 3 stamens, and seeds without albumen. 



At this point there is an abrupt break in the series of direct affinity. No gradual 

 change can l>e traced from othe/natural Orders to that of the Orchidal Alliance, which 

 is distinguished by the embryo not only having no albumen, but being a solid 

 homogeneous body, equally destitute of any visible radicle or cotyledon. In the 

 majority the structure is what Linnteus called Gynandrous ; that is to say, the stamens, 

 and style, and stigma, are blended together into one solid body, named a column ; in 

 two, however, of the natural Orders of which it consists, the stamens are perfectly free. 

 If we neglect the condition of the seeds, we then may find a variety of approaches to 

 other Orders, as, for example, to the Irids, in which Gladiolus seems to be an 

 imitation of the structure of an Orchis ; or to Sisyrinchium, to which Thelymitra or 

 Paxtonia offer some analog}' ; or to the Hypoxids, of which Apostasias and Tropidia 

 have much the aspect ; or to Gingerworts, whose close heads of imbricated bracts are 

 imitated in Evelyna. The Burmanniads are remarkable for their perfect symmetry, 

 among hundreds of species whose prevailing character is want of symmetry. 



Natural Orders of Orchidals. 



Flowers regular. Stamens free, perigynous 51. Birmanniace-E. 



Flowers iiTcgular, gynandrous. Placenta parietal 52. Orchidace.e. 



Flowers regular, half -gynandrous. Placenta axile 53. Ai'OSTasiace-e. 



