Chap. V. MALAXIS PALUDOSA. 131 



its position it partially protects the organs of fructi- 

 fication (fig. 19). In most of the Orchideae, the upper 

 sepal and the two ujjper petals afford protection ; but 

 here these two petals and all the sepals are reflexed 

 (as may be seen in the drawing, fig. A), apparently to 

 allow insects freely to visit the flower. The position 

 of the labellum is the more remarkable, because it 

 has been purposely acquired, as shown by the ovarium 

 being sjjirally twisted. In all Orchids the labellum 

 is properly directed upwards, but assumes its usual 

 position on the lower side of the flower by the twist- 

 ing of the ovarium ; but in 3Ialaxis the twisting has 

 l)een carried so far that the flower occupies the posi- 

 tion which it would have held if the ovarium had 

 not been at all twisted, and which the ripe ova- 

 rium afterwards assumes, by a process of gradual 

 untwisting. 



When the minute flower is dissected, the column is 

 seen to be longitudinally tripartite ; the middle 

 portion of the upper half (see fig. B) is the rostellum. 

 The upper edge of the lov/er part of the column 

 projects Avhere united to the base of the rostellum, 

 and forms a rather deep fold. This fold is the stig- 

 matic cavity, and may be compared to a waistcoat- 

 pocket. I found pollen-masses which had their broad 

 ends pushed by insects into this pocket ; and a 

 bundle of pollen-tubes had here penetrated the 

 stigmatic tissue. 



The rostellum, which stands immediately above the 

 stigmatic cavity, is a tall membranous projection of a 

 whitish colour, formed of square cells, and is covered 

 with a thin layer of viscid matter : it is slightly con- 

 cave posteriorly, and its crest is surmounted by a 

 minute tongue-shaped mass of viscid matter. The 

 •column, with its narrow pocket-like stigma and the 



K 2 



