APPENDIX A 



499 



the front facing the bract. This is essential for the success of the strongly 

 zygomorphic flower as a pollinating mechanism. 



The ground-plan of the flower is shown in Fig 402, iv. ; it consists of : 

 Perianth, segments 3+3, polyphyllous, superior. The three outer segments 

 are small, and of about equal size, the odd one being anterior (i). The three 

 inner are very unequal. The posterior segment, turned by resupination to 

 the front, forms a large platform, or labellum (6), and it is dilated downwards 

 into a long spur (sp). The two smaller, together with the outer anterior 



H. 



FIG. 402. 



Flower of Orchis maculata, L. I. Whole flower in frontal view. II. Lateral 

 aspect, perianth partly removed. III. Young fruit. IV. Floral diagram. V. VI. 

 Pollinia in erect and curved positions. 1-6 = perianth-segments ; (i) is really the 

 anterior, but by resupination the posterior segment ; 6 is the labellum, actually 

 posterior, but by resupination the anterior segment. B= bract; s=spur; ov = 

 ovary; s= stigma; r= rostellum. 



segment, form a hood-like group over the column, which rises just behind 

 the open entrance to the spur. It is the result of fusion of the single stamen 

 with the short style. 



The Androecium is represented only by a single anterior, fertile stamen, which, 

 owing to the resupination, faces the observer : each of its two purple 

 anther-lobes shows when ripe a longitudinal slit of dehiscence. The down- 

 ward directed, but really apical end of the anther is covered by the small 

 globular rostellum, which obstructs the entrance to the spur (Fig. 402, I. n.). 



The Gynoecium consists of three carpels, syncarpous and inferior. Of the 

 three stigmas one which is not receptive is represented by the rostellum (r), 

 the other two are merged into a hollow oval stigmatic surface situated below 

 the rostellum (s). A transverse section of the ovary, preferably of a flower 

 already fertilised, shows a single cavity, with three parietal placentas, and very 

 numerous minute ovules. 



