THE IRIS FAMILY. 153 



3. Study carefully the modifications exhibited by this 

 flower, as compared with the lily taken as a type. 

 Have any parts been suppressed ? Does adnation 

 occur? What are some of the most striking pecu- 

 liarities of form and structure ? 



II. Examine each part in detail with reference to the 

 arrangements for cross-fertilization. 



1. Enumerate the attractive features. 



2. Ascertain whether there is a store of nectar, and if so 



whether there are any path-pointers to direct visit- 

 ing insects towards it. 



3. Observe particularly the position of stamens and 



stigma. 



a. Position of the anther and its mode of dehiscence. 



b. Location of the stigmatic surface. Examine 



under a good lens. 



" The curved style-branches have at their tip a small 

 deltoid crest which turns slightly backward. Under this 

 there is a thin shelf, the upper surface of which is covered 

 with minute hairs, and is moistened with a sticky secretion. 

 This shelf is the true stigma." Verify this description as 

 given by Dr. Goodale, Wild Flowers of America, p. 34. 



What do all these peculiarities of structure, color, and 

 arrangement suggest? Do you regard self-fertilization as 

 possible in this species? If you infer that cross-fertiliza- 

 tion takes place, show how this is probably brought about. 1 



BLUE-EYED GRASS. Sisyrinchium angustifolium, Mill. 



This species is widely distributed, and continues to 

 flower for some weeks, so that it can usually be obtained 

 for comparison. 



1 Cf. Gray, How Plants Behave, pp. 21, 25 j Miiller,' Fertilization of 

 Flowers, p. 543 et seq. 



