170 ORCHID ALES. [Endogens. 



Alliance XIII. OECHIDALES.—Tre Orchidal Alliance. 



Diagnosis. — Epigynous Endogens, vjith I to d stamens, and seeds without albumen. 



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

 change can be traced from other natural Orders to that of the Orchidal Alliance, which 

 is distinguished by the embryo not only ha%ang no albumen, but being a sohd 

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

 majority the stractiu-e is what Linnaeus called Gjniandi'ous ; that is to say, the stamens, 

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

 two, however, of the natm-al 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 wliich Gladiolus seems to be an 

 imitation of the structm^e of an Orchis ; or to Sisyrinchium, to which Theljnnitra or 

 Paxtonia offer some analogy ; 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 himdreds of species whose prevailing character is want of symmetry. 



Natural Orders of Orchidals. 



Flowers regular. Stamens free, perigynous 51. Burmanniace^. 



Floioers irregular, gymmdrous. Placentce pa)%etal 52. Orchidace^. 



Floivers regular, half-gynandrous. Placentce axile 53. Apostasiace^. 



