374 VARIOUS PLANT GROUPS 



two coalescent and adherent bractlets. Plants with both 

 staminate and pistillate inflorescences borne upon the same 

 individual plant are termed monoEcious.^ 



The united bracts and bractlets of birches (Betula) ripen 

 into dry scales forming a cone-like cluster of fruits made up 

 of little samaras. In hazels the involucre becomes much 

 enlarged in fruit, and each surrounds a much hardened peri- 

 carp which because of its hardness and indehiscence is called 

 a nut^ 



The family comprises woody 'plants without oil reservoirs 

 but with resinous icarts or hairs on the younger parts; simple, 

 stipulate leaves; and monoecious inflorescences, the staminate 

 amentaceous, the pistillate in spikes or heads with coalescent 

 bracts and bractlets, and the pistils of two carpels with axile 

 placentae. 



123. The beech family (Fagaceae). Examples: chest- 

 nut (Figs. 24-26, pages 37, 38), oaks (Figs. 242, 243, 267, 

 pages 257, 258, 277), and beech (Fig. 257, page 268). 



See pages 414, 415 for the formulas of Fagus, Castanea, Quercus, 

 and Fagacese. 



The inflorescences of this family resemble those of the 

 preceding family in being monoecious and in part amenta- 

 ceous. It is in the bracts and the way they are borne that 

 we find the most significant differences — differences which 

 become more striking as the fruit matures. Indeed, bot- 

 anists have here met with a morphological problem of more 

 than ordinary difficulty in the preliminary question: What 

 are the homologues of bracts which ripen with a beechnut, 

 a chestnut-bur, or an acorn? 



In the staminate inflorescences of beech (Fagus) and chest- 

 nut (Castanea) the bracts are obvious enough and are suffi- 

 ciently like those of the birch family to require no special 



1 Mo-noe'cious < Gr. monos, one; oikos, household. This is indi- 

 cated by cf-9 . If the staminate inflorescence differs in form from 

 the pistillate the nature of each is shown by placing the inflorescence 

 signs in corresponding order, i. e., beginning with the staminate. Thus 

 li-i" would read "staminate inflorescence amentaceous, the pistillate 

 spicate, both compounded of heads." 



2 In the formula this extra hardness of the pericarp is indicated by 

 two inverted exclamation points. 



