4i8 THE FAGALES 



beam the bract forms a papery sac about the nut, in the hazel 

 a leafy husk (Fig. 298), in the birch and alders a woody peg- 

 like structure. In the chestnut and beech the pistils are com- 

 pletely enveloped by prickly bracts or outgrowths that form the 

 bur (Fig. 300, A-C), while in the oak these structures only cover 

 the lower portion of the ovary, forming the cup (Fig. 299, C-E). 

 The flowers of this order are typical of that great group of plants 

 comprising about one tenth of all the flow^ery plants, which are 

 called anemophilous. Note the small and simple flowers, absence 

 of showy perianth, nectar, and odor glands, dry and light micro- 

 spores lavishly produced to ensure crossing and the delicate 

 bushy stigmas for catching the spores. The stigmas appear a 

 day or so before the adjoining microspores are being shed so 

 that a crossing from an earlier flowering plant is necessitated. 

 These plants form the larger part of our deciduous forests and 

 their association in colonies is doubtless connected with their 

 anemophilous habit, as is also the appearace of the flowers before 

 the leaves are fully developed. The positions assumed by the 

 staminate aments is of service in protecting the microspores 

 against wetting and also to assist in their distribution. During 

 the winter, these aments are quite erect but as the flowering stage 

 approaches they become pendulous, the larger bracts protecting 

 the sporophylls, like the shingles on a roof (Fig. 298, A). These 

 bracts, being hygroscopic, remain closed during wet weather but 

 on dry days they curve back, each bract forming a shelf which 

 serves to catch the spores when no winds are stirring and thus 

 prevent their falling to the ground. 



140. Other Tree Orders Suggestive of the Fagales. — Closely 

 allied to the Fagales is the order of the walnuts, Juglandales, 

 including the black walnut and butternut {Juglans) and the hick- 

 ories {Hicoria, Fig. 301). These trees are of very common 

 occurrence in the northern United States and are characterized 

 by aromatic oils and large compound leaves. The flowers are 

 very similar in structure and arrangement to those of the beech 

 order, but at maturity the outer part of the wall of the ovary 

 becomes transformed into a fleshy rind and the inner portion 

 forms a hard shell. In the walnut this pulpy, aromatic rind 



