Orchideous Plants of Chile. 53 



writing " Serapias Gavild de Chile sp. nov. ined." It is pro- 

 bably from the north of Chile, and is very different from the 

 Gavilu of Feuillee, which is a species of Chlorsea. 



The three genera, Chlorsea, Bipinnula, and Asarca, represent 

 the form of Chilian Orchideaj under the three modifications to 

 which it is probable that they are subject. Collectively they 

 constitute a tribe of Arethusese with distinct sepals, having an 

 expansion which is always more or less ringent, with a columna 

 having membranous margins, and with a cucullate, crested la- 

 bellum. Individually they are recognised by the particular state 

 of the lower sepals, and the condition of their parenchymatous 

 matter. Chlora?a and Bipinnula are distinguished from Asarca 

 by a tendency in the anterior parts of the flower to anamor- 

 phosis, or an excessive production of parenchyma, while Asarca 

 is characterised by the want of such a tendency, except in the 

 labellum, in which anamorphosis exists in no greater degree 

 than in many other Orchideae. That the peculiarities of the 

 anterior sepals of both Chloraea and Bipinnula depend upon the 

 condition I have stated, may, I think, be easily shown, not- 

 withstanding their apparent difference of anatomical structure. 

 In the species of Chlorsea the sepals are entire, and the excess 

 of parenchyma is insufficient to overcome the resistance or 

 power of expansion of the cuticle ; while in Bipinnula, in which 

 the sepals are plumose, the anamorphosis is so much increased 

 as to overcome the resistance of the cuticle, and the paren- 

 chyma is consequently no longer confined within a narrow 

 space forming a sort of succulent bag, but pushes forth on all 

 sides with nearly equal power, in the form of a membranous fea- 

 thery fringe of the most beautiful symmetry. That these two 

 forms do in fact depend upon such a power of parenchymatous 

 development as I have assumed, seems to be in some measure 

 proved by this circumstance ; that while the anterior sepals 

 are entire (and the power of developement therefore weak), 

 they bear the same proportion to the other parts of the flower 

 as is usual in Orchideae ; but as soon as the anterior sepals 

 become feathery (and the power of developement therefore 

 excessive), they no longer bear the usual proportion to the 

 posterior sepals, but become elongated in the same degree as 

 they become fringed or laterally developed and membranous. 



