MONOCOTYLEDONES 



191 



spurred ; sometimes the labellum exhibits a di"\dsion into three 

 regions, of which the lowest is then termed the hyjjochilium, 

 the middle the mesochiimm, and the upper the eiyicliilium. 

 Androecium united to the style {gynandrous) and forming with 

 it a central column (gynostemium) ; the column usually bearing 

 one perfect anther and two lateral abortive ones, or in Cyjjri- 

 jjediuin two lateral perfect anthers and one abortive anther in 

 the centre. Pollen powdery, or more or less collected into 

 grains or waxy or meal}' masses {^oUinia) ; the masses free, or 



FiCt. 938. 



Fig. 939. 





Fm. 940. 



Ftg. 941. 



Fig. 938. Front view of the flower of the Tway-blade {Listera ovata), 

 showing the bifid labellum at the anterior part of the flower, and the 

 other five divisions of the perianth ; the one stamen and three styles 



forming a column (giinostemium). Fig. 939. Diagram of the flower of 



an Orchid, s, si, si. The three outer divisions of the perianth ; s being 

 anterior or inferior, si, si, being lateral, pi, pi. The two lateral divisions 

 of the inner whorl of the perianth, ps. The superior or posterior division 

 (labellum) of the inner whorl ; this by the twisting of the ovary becomes 

 ultimately inferior or anterior, e. The fertile stamen, with two anther 

 lobes, c. Transverse section of the ovary, with three parietal placentas. 



Fig. 940. Fruit of an Orchid dehiscing by three valves, each valve 



bearing a placenta and numerous very minute seeds. Fig. 941. Seed 



of an Orchid, y^ith a loose reticulated testa. 



attached by their stalk, c {caudicle), to a gland or glands 

 {retinacula) at the apex {rostellum) of the stigma. Ovary 

 inferior, 1-celled, with 3 parietal placentas bearing a number of 

 anatropous ovules ; style united with the androecium and form- 

 ing with it a column or gynostemium ; stigma a viscid space 

 in front of the column. Fruit usually capsular, 3-valved, the 

 valves bearing the placentas in their middle, and separating 

 when the fruit is ripe from the central parts or midribs of the 

 component carpels, which are left as an open framework ; or 



