4i6 THE SALICALES 



travagant production of microspores and the formation of the 

 flowers before the leaves become large and so interfere with the 

 distribution of the microspores are all characteristics of anemoph- 

 ilous flowers. It is noteworthy, however, that nectar glands 

 are developed in the flowers of the willow (Fig. 297, D, n) and 

 that the microspores are sticky, indicating that these flowers are 

 entomophilous. Perhaps we have here an illustration of one of 

 the earliest variations of the flower that served as an allurement 

 to insects. Certainly, the nectar glands and the conspicuous dis- 

 play of microsporophylls are a very efficient attraction, as is at- 

 tested by the variety of insects that swarm about the aments. 



The most efficient factor in the distribution of the willows and 

 poplars is found in the seed. The megasporophylls mature in the 

 early summer, when the two carpels spread apart (Fig. 297, 

 G~I), permitting the discharge of the seeds, which are provided 

 with a circle of hair at the base (Fig. 297, J). This parachute 

 is not so nicely constructed as in Typha, but it is so efficient 

 that myriad numbers of minute seeds are carried a considerable 

 distance and cover everything in the neighborhood of the trees 

 with their lint-like masses. The name cottonwood is popularly 

 applied to several of the poplars because of the cotton-like clusters 

 of seeds that emerge from their aments. 



139. Fagales, the Bejlch Order. — This order includes many 

 of the most important hard-wood trees of the temperate regions, 

 comprising the family of the birches, with such representatives 

 as the American hornbeam (Carpinus), hop hornbeam (Ostrya), 

 hazel {Corylus), birch (Betula), alder (Alnus) and the beech 

 family, which includes the chestnut (Castanea), beech {Fagus) 

 and oak (Quercus). The inflorescence is more commonly an 

 ament as in the preceding order (Figs. 298, A ; 299, A), although 

 in the hazel and in the beech family only one or a few pistils are 

 developed in the bud-like clusters of overlapping bracts (Fig. 

 299, p). The flowers are imperfect and the two kinds of sporo- 

 phylls are usually developed upon the same plant. Several bracts 

 are usually associated with sporophylls (Figs. 298, B-F; 290, 

 B-E) so that the flowers are of a higher type than the willows. 

 The innermost of these bracts is often of a delicate structure and 



