346 



DICOTYLEDONES. 



the four valves in the cupule of Castanea are considered as 

 bracteoles of the lateral flowers of the dichasium) ; according to 

 another view (see Prantl, in Engler's Bot. Jahrb., viii., 1889), it is 

 a ring-like axial outgrowth independent of the bracteoles of the 

 flower, whose scales and spines are floral-leaves. The cupule in 

 the Oak only encloses the base of the fruit, but in the Eating- 

 chestnut and Beech the fruit is completely enclosed, and con- 



FIG. 332. Castanea vnaca : A branch with inflorescences; B <J. flower; C young cnpule 

 with three ? -flowers; D ? -flower; E the same in longitudinal section; F cupule with 

 3 nuts (diminished) ; G, H nuts ( in longitudinal section to show embryo). 



sequently the cupule must divide into a number of valves (gener- 

 ally 4) to allow the fruit to escape. In the 3-flowered dichasia 

 of Pasauia, Sect. Eupasania (Trop. Ind.), each individual flower 

 has its own cupule of the same structure and development as in 

 Quercus, and, moreover, each group of flowers has externally the 

 typical six bracteoles. 



Castanea (Eating-chestnut, Fig. 332). The catkins are erect 



