THE PROMISE OF THE PLANT THAT IS TO BE 



489 



FIG. 609. CONE or CHINESE 

 ARBOR- VIT^E (Thuja orientalis). 



In the Oak (Quercus, fig. 624) the nuts, 



usually called acorns, are seated in cups or 



cupules of bracts, which, curiously enough, 



are only formed after fertilization. In the 



British Oak (Quercus robur] these cups are 



rough on the exterior ; but in those of the 



Turkey Oak (Quercus cerris) they are coated 



with moss-like outgrowths. The order Cupu- 



liferce derives its name from these vegetable 



cups. Beech-nuts, the fruits of Fagus syl- 



vatica : are contained in a spiky husk the 



enlarged four-partite involucre of bracts 



which, on a superficial view, might be mis- 

 taken for the pericarp. Each involucre 



usually contains one or two nuts, which 



are sharp-cornered and triangular, and which, on 

 the splitting of the husk in the autumn, fall to the 

 ground. 



Fruit dispersion in cupuliferous plants is largely 

 assisted by animals. " Many noble oaks," says a 

 writer in the Zoologist, quoted by Dr. Cooke, " have 

 been planted by the squirrel, who unconsciously 

 yields no inconsiderable boon to the domain he in- 

 fests. Towards autumn this provident little animal 

 mounts the branches of Oak-trees, strips off the 

 acorns and buries them in the earth, as a supply of 

 food against the severities of winter. He is most 

 probably not gifted with a memory of sufficient re- 

 tention to enable 



him to find every one he secretes, which 



are thus left in the ground, and springing 



up the following year, finally grow into 



magnificent trees. Pheasants devour num- 

 bers of acorns in the autumn, some of 



which, having passed through the stomach, 



probably germinate." 



A dry fruit whose leathery pericarp 



closely adheres to the seed-coat is termed 



a caryopsis. This is the characteristic fruit 



of the family of Grasses. The Wheat- 

 plant (Triticum) presents a good type of 



the caryopsis. A full-grown and perfect 



grain of wheat will, on examination, be Flo _ 6 n._ G ouBD (Cucurbita pepo). 



found tO resemble the accompanying figure A berry with hard exterior; also called a pepo. 



FIG. 610. MILK- THISTLE 

 (Silybum marianum). 

 Cypsela with sessile pappus. 



