CHAP. VI. FUNCTION OF REPRODUCTION. 2?9 



is very small and unbranched, it is easily torn up by 

 the force of the wind, and the plant is then blown 

 along the surface of the soil until it happens to arrive 

 at some pool of water, when the branches imbibe 

 moisture and unrol : the pericarps also burst and the 

 seeds are disseminated in a spot where they are able to 

 germinate. 



(280.) Hypocarpogean Fruits. There are some 

 plants which possess the singular property of ripening 

 their seed under the ground. In some of these the 

 blossoms expand in the air, and then the pericarp is 

 drawn down or forced underground by the incurvation 

 of the pedicle, as in the Antirrhinum Cymbalaria, 

 Cyclamen, &c. The Trifolium subterraneum, a small 

 species of clover not uncommon in the sandy districts 

 of England, has its flowers arranged four or five in a 

 head : the end of the pedicel emits some succulent 

 spinous processes, which soon harden, and the whole is 

 gradually thrust under the surface of the soil, where 

 the seeds ripen and germinate. 



Some plants possess two distinct modes of flowering, 

 the one aerial and the other subterranean ; and these 

 either perfect the fruit on both stems, as in the Vicia, 

 amphicarpos ; or else that which is produced on the un- 

 derground stems alone arrives at perfection, as in the 

 Arachis hypogcea, or ground-nut. 



(281.) Preservation of Seeds. Notwithstanding 

 the ample provision which is made for securing a super- 

 abundant crop of seeds, infinitely beyond the number 

 of individuals destined to spring up from their disse- 

 mination, there is another circumstance to be noticed in 

 their history, which most materially diminishes the 

 chance of any species being extirpated. This is the 

 property which seeds possess of resisting decomposition, 

 and of retaining their vitality whenever they are placed 

 under circumstances favourable to their preservation. 

 Seeds are capable of being longer preserved in propor- 

 tion as they have been more thoroughly matured ; and 

 hence it is advisable to allow them to remain for a 



T "t 



