240 HOMOLOGIES OF THE Chap. VIEL 



all were observed excepting a^, which is the most 

 difficult one to trace, and apparently is oftenest absent. 

 In the CypripedccTe, again, all were traced except ag,* 

 which, I feel pretty sure, was here really absent : in 

 this tribe the stamen (Ai) is represented by a con- 

 spicuous shield-like rudiment, and ai and a^ are 

 developed into two fertile anthers. In the Ophre^B 

 and NeottCcTB all were traced, with the important 

 exception of the vessels belonging to the three stamens 

 («!, ^2, and %) of the inner whorl. In Gejjhalanthera 

 grandiflora, I clearly saw a^ proceeding from the 

 anterior ovarian group, and running up the front of 

 the column. This anomalous Orchid has no rostellum, 

 and the vessel marked S^ in the diagram was entirely 

 absent, though seen in every other species. 



Although the two anthers {a^ and a^ of the inner 

 whorl are not fully and normally developed in any 

 Orchid, excepting Cypripedium, their rudiments are 

 generally present and are often utilised ; for they often 

 form the membranous sides of the cup-like clinandrum 

 on the summit of the column, which includes and pro- 

 tects the pollen-masses. These rudiments thus aid 

 their fertile brother-anther. In the young flower-bud 



supplying the fertile anther runs tion of a freo filament in front of 



up the connective membrane be- the labelhim, as in the ease of 



tween the two anther-cells, but Glossodia before mentioned ; and 



does not bifurcate : the ves-el to tliis will perhaps account for thu 



the rostellum runs up to the top absence of spiral vessels, proceed- 



of the shoulder or ledge beneath ing from the anterior ovarian 



tlie connective membrane of tlie group and coalescing with the 



anther, but does not bifurcate and column. In Uropedium, a genus 



extend to the two widely-separated which A. Brongniart (' Annal. 



viscid discs. des. Sc. Nat.,' 3rd series, Bot. torn. 



* From Irmisch's ('Beitrdge xiii. p. 114) considers closely allied 



zur Biologic der Orchidecn,' 1853, to, and even perhaps a monstro- 



pp. 78 and 42) description of the sity of, Cypripedium, a third fer- 



development of the flower-bud of tile anther occupies this same 



Cypripedium, it would appear that position, 

 there is a tendency to the forma- 



