222 THE OIICHIDACE.E OF THE 



are all agreed. This, then, is the characteristic, of the Orchis 

 tribe. I will now proceed to give a detailed description of the 

 construction and manner of fertilisation of Orchis viasada, Ophrys 

 imiscifera, and Ophrys apifera. Space will not permit me to 

 attempt more than this. 



First, let us take Orchis mascula (Early Purple Orchis). The 

 accompanying sketches (PL XXIV., Figs. 6, 8, and 9) show the 

 relative position of the more important organs in this flower. The 

 sepals and petals have been removed, excepting the labellum, with 

 its nectary. The nectary is shown only in the side view (Fig. 6) ; 

 its enlarged orifice is almost hidden in shade in the front view. 

 The stigma is bilobed, and consists of two almost confluent stigmas ; 

 it lies under the pouch-formed rostellum. The anther a (Figs. 6 

 and 9) consists of two rather widely separated cells, which are 

 longitudinally open in front ; each cell includes a pollen-mass 

 or poUinium. A pollinium removed out of one of the two anther- 

 cells is represented by Fig. 7. It consists of a number of wedge- 

 shaped packets of pollen-grains, united together by excessively 

 elastic thin threads. These threads become confluent at the lower 

 end of each pollen-mass, and compose the straight elastic caudicle. 

 The end of the caudicle is firmly attached to the viscid disc, d^ 

 which consists of a minute oval piece of membrane, \\\i\\ a ball of 

 viscid matter at its under side. Each pollinium has its separate 

 disc, and the two balls of viscid matter lie enclosed together 

 within the rostellum (PI. XXIV., Fig. 8). The rostellum is 

 a nearly spherical, somewhat pointed projection (Figs. 6, 8, and 

 9), overhanging the two almost confluent stigmas, and must be 

 fully described, as every detail of its structure is of great significa- 

 tion. A front view of both viscid discs within the rostellum is 

 given at d^ d, Fig. 8. This latter figure (8) probably best serves to 

 explain the structure of the rostellum ; but it must be understood 

 that the front lip is here considerably depressed. The lowest 

 point of the anther is united to the back of the rostellum, as may 

 be seen in Fig. 9. At an early period of growth the rostellum 

 consists of a mass of polygonal cells, full of brownisli matter, 

 which cells soon resolve themselves into two balls of an extremely 

 viscid semi-fluid substance, void of structure. These viscid 

 masses are slightly elongated, rather flat on the top, and convex 



