232 



THE FLOWEIv. 



copiously secreted and contained. The central part of the 

 blossom, beyond the orifice of the nectary (shown separately in 

 Fig. 461), consists of one anther and a stigma, fused together 

 (the dinandrium) : the marginal portions, opening by a long 

 chink, are the two cells of the anther, approximate at their 

 broader portion above, widely divergent below : most of the 

 lower part of the space between is excessively glutinous, and is 

 the stigma. The grains of pollen are united b}" means of short 

 threads of very elastic tissue into small masses, and these into 

 larger, and at length into pellets, having stalks of the same 

 elastic tissue, by which they are 

 all attached to a firmer central 

 stalk, or caudick. (Fig. 463-465.) 

 To the lower end of this caudicle 

 (directly to the end of it in our 

 Habenariae and Orchises gener- 

 ally, in this instance to the inner 

 side of the end, with a thick inter- 

 mediate base intervening), is at- 

 tached a button-shaped disk, the 

 face of which is exposed, and is 

 on a line with the surface of the 

 anther ; so that these two disks 

 look toward each other across the 

 broad intervening stigma tic space, 

 as seen in Fig. 461. The exposed 

 face of the disk being covered with 

 a durable layer of very viscid mat- 

 ter, the body itself is sometimes termed a gland, and not improperly. 

 The viscidity is nearly of the same nature as that of the interven- 

 ing stigma, of which the glands are generally supposed to be 

 detached portions. If so, then a portion of the stigma is cut off 

 from the rest and specialized to the purpose of conveyance of the 

 pollen. When a finger's end or any smaller body is touched to 

 these disks, the}' adhere so firmly that the attached pollinia or 

 pollen-masses are dragged out of the cell and carried away en- 

 tire. Some of these pollen-masses have been found attached by 

 the disk to the eyes of a large moth. "When a moth of the size 

 of head and length of proboscis of Sphynx drupiferarum visits a 

 spike of these flowers, and presses its head into the centre of the 



FIG. 463. A more magnified pollen-mass of Platanthera orbiculata. with its stalk 

 and gland. 464. Five of the separate portions or pollen-packets, with some of the 

 elastic threads of tissue connecting them. 465. A portion more highly magnified, with 

 some of the pollen-grains in fours detached. 



