172 Dr. F. Hildebrand on the Impregnation in Orchids 



soon as those that are impregnated ; their ovules- show in most 

 cases no further development ; they sometimes become a little 

 more perfect, but are always decomposed before the ovarium 

 has withered and the flower has fallen off. After the stigmata 

 of the flower are impregnated with pollen, in most cases the 

 sepals and petals soon wither, but do not fall ofi^, and are still to 

 be found in a dry state at the top of the ripe fruit ; sometimes 

 they fall ofi" in a few days. One curious case occurred in 

 Listera ovata, where they change very little after impregnation, 

 and were still found in a fresh and succulent state on the top of 

 the ripe dehiscing capsule. 



3. The time that elapses between the application of the pollen 

 to the stigma and the full development of the ovules and the 

 formation of the embryo depends on the degree of development 

 of the ovules in the recently expanded flower. This fact might 

 have been suspected, but it will appear to be made out sufficiently 

 after looking at the following summary (in which ii means the 

 integumentum internum, the inner coat ; ie, the outer ; n, the 

 nucleus) : — 



Time from the application of Pollen 

 to the Stigma to the incipient 

 formation of the Embryo. 



Neottia nidus-avis, May 24 to June 2; 



8-9 days. 

 Listera ovata, May 8 to 17 ; 9 days. 

 Orchis pyrumidalis , June 22 to 



July 1 ; 8-9 days. 

 Orchis coriophora, June 14 to 23; 



9 days. 

 Gymnadenia conopsea, June 8 to 23; 



about 2 weeks. 

 Orchis Morio, May 9 to 22 ; about 



2 weeks. 



Orchis maculata, June 8 to 25 



2^ weeks. 

 Orchis hircina, May 24 to June 13 



3 weeks. 



Orchis latifolia. May 17 to June 3 



2\ weeks. 

 Ophrys my odes, May 24 to June 13 



3 weeks. 



Orchis mascula, April 22 to May 22 



4 weeks. 



Orchis mascula, May 3 to 24 (?) 



3 weeks 

 Platanthera chlorantha. May 24 to 



June 17; 3^ weeks. 

 Orchis militaris, May 15 to June 16 ; 



more than Ah, weeks. 

 Cypripedium laticolus, May 16 to 



June 20 ; 5 weeks. 



Degree of Development of the Ovules 

 in the expanded Flower. 



Ovules inverted, ii overlapping n, 

 ie not yet overlapping ii. 



The same. 



Inverted, acorn-Uke, ii and ie not 

 yet overlapping n. 



The same. 



Inverted, ii beginning to appear. 



The same. 



The same. 



Inverted, ii and ie beginning to 

 appear. 



Inverted, ii beginning to appear. 



The same. 



Straight papillae, seldom a little 

 incurved, with the beginning of ii. 

 The same. 



Straight papillae, seldom a little 

 incurved, without the beginning of ii. 

 The same. 



Papillae a little incurved ; begin- 

 ning of ii very small. 



