I INTEODUCTION 15 



cannot correlate this with the leaf - arrangement or 

 derive it in any simple way from a pentamerous flower 

 — it is a remarkably constant type of flower, and the 

 story of its development is lost. Last come such cases 

 as the Lilac and Privet, where the leaves are in pairs, 

 and opposite, so that the whorl would consist of four 

 leaves. 



Fruits and Seeds 



As regards fruits and seeds, one main point to be 

 considered is the mode in which they are dispersed. 

 From this point of view they may be divided into 

 various classes : — 



Seeds or fruits with wings, which are carried by 

 wind. 



Seeds or fruits with feathery appendages, carried 

 by wind, and sometimes, as in Willow, floated by 

 water. 



Seeds in capsules which open at the top, the seeds 

 being jerked out by wind. 



Seeds or fruits with hooks, which are carried by 

 animals. 



Fruits which are eaten and the seeds thus carried by 

 animals. 



Seeds which are thrown by the plants. 



To the first category, viz., those with wings, belong 

 mainly trees : as, for instance, Pines and Firs, Syca- 

 mores and Maples, Elms and Birch ; while though the 

 fruit of the Lime is not itself winged it is attached to a 

 leafy bract which serves the same purpose. The same 

 is the case with the Hornbeam. 



The next class, those with hairy appendages, is very 

 extensive. To it belong the Willows and Tamarisks, 

 many Grasses, Bulrushes, Cotton-grass, Willow-herbs, 

 Dandelion, Thistles, and many other Composites, etc., 

 etc. 



Examples of plants in which the fruits or seeds are 

 provided with hooks are found in Agrimony, Bur- 

 parsley, Burdock, Carrot, Cleavers (Galium), Enchanter's 



