38 FERTILIZATION OF THE FLOWERS. 



close fertilized, are usually anemophilous, fertilized by the aid of 

 the wind. In a few cases, insects visit the flowers quite regularly 

 for pollen, and most likely render aid in the fertilization. The 

 writer has several times seen large numbers of honey bees, early 

 in the day, gathering the pollen of Festuca arundinacea. 



Bucliloe (buifalo grass) is an example of those which are 

 dioecious, and of course the flowers are all cross-fertilized. 

 Indian corn, Zizcmia (wild rice) and Tripsacum (gama-grass) are 

 monoecious and are very likely to be crossed. In some cases of 

 Indian corn, and probably it is so with some other species, the 

 flowers are protogynoiis, i. e., the pistils come forth a day or more 

 in advance of the anthers. In other cases, as for example, sweet 

 vernal grass and meadow fox tail, the flowers are proterandrous, 

 i. e., the anthers mature in advance of the pistils. In either plan, 

 cross fertilization is secured. 



The spikelets of Arrlienatlurum avenaceum (tall oat-grass), 

 and others, contain a staminate or sterile flower to every perfect 

 one, and the flowers of Hierocliloa lorealis (vanilla grass), are 

 two of them staminate to one that is jjerfect. The use of 

 these staminate flowers can only be for crossing. Some culti- 

 vated plants 6f A. avenaceum bear only staminate flowers. 



In many cases where the flowers are perfect, the stamens shed 

 their pollen before the stigmas are ready, or the reverse is the 

 case. 



In some instances the stamens and pistils appear to mature at 

 the same time, as in most, if not all, sorts of cultivated wheat, 

 barley, oats and rye. In the three former, the glumes and paleae 

 usually closely cover up the stigmas till they are fertilized or 

 covered with pollen. The glumes of rye spread so that cross- 

 fertilization may take place. Ampliicarpum, Oryza clandestina, 

 some species of Ilordeum and Cryptostachys, and most likely 

 others, produce fertile flowers below ground, and are called 

 cleistogamic. 



