1528 A TEXTBOOK OF THEORETICAL BOTANY 



carpel, the pericarp being papery, leathery or woody. 

 Examples: Ranunculus, Alisma. 

 (b) Nut (Nux). A single-seeded indehiscent fruit arising from 

 a pluricarpellary ovary, by abortion of all but one developing 

 ovule. Examples: Valerianella, Tilia. 



Fig. 1 39 1. — Group of akenal fruits, including, from the top left hand downwards: 

 Atriplex, Hdideutn, Trcigopogon, Carduiis, Triticiuu, Areini, Zea. 



{c) Cypsela. An akene formed from an inferior ovary. It is 

 thus sheathed with other floral tissues in addition to the 

 ovary wall and is strictly a " false fruit". Example: 

 Compositae. 



{d) Caryopsis. An akene in which the pericarp and the testa 

 are indissolubly united. Examples: Gramineae, with the 

 exception of Bambuseae in which the pericarp is distinct 

 from the testa. 



{e) Samara. A winged akene. Examples: Fraxinus, Ulmiis. 



The term Nut is unsatisfactory in that it is applied in a sense very 

 different from that of ordinary usage. The fruits of Corylus and Quercus 

 arise from inferior ovaries and although they correspond otherwise to the 

 definition of a nut, they are distinguished by the term Glans. Certain other 



