DISPERSAL OF SEEDS 77 



probably be carried to some little distance before they reach the 

 ground. The winged seeds of the Pine (Vol. IV. p. 66) serve the same 

 purpose. The thin flat halves of the fruit of the Cow-Parsnip 

 (Vol. IV. p. 6, Fig. 3) are also suited to be wind carried. The most 

 beautiful arrangements for wind-dispersal are shown, however, 

 by somewhat smaller fruits or seeds, which may often be carried 

 long distances before they reach the ground. The parachute-like 

 group of hairs on the seeds of the Willow Herb (Vol. IV. p. 20, Fig. 5) 

 and Willow (Vol. IV. p. 48) and on the fruits of the Dandelion 

 (Vol. III. p. 148) lead to the seeds or fruits being easily carried by 

 even a gentle movement of the air. Every one knows the way in 

 which Thistle-down is carried to a distance when the fruits are 

 ripe and becoming detached from the inflorescence. 



Another great agency for the dispersal of fruits is afforded 

 by the power of movement possessed by birds and mammals. 

 Animals are of use in dispersing fruits in two main ways. Many 

 fruits have rough surfaces, recurved hairs or hooks which will 

 catch readily in the fur or feathers, and not be loosened until the 

 animal is some distance from the plant. No very good examples 

 of this method of dispersal are among the plants described. The 

 hooked style of the fruitlets of the Avens (Vol. III. p. 216) serve 

 this purpose, however. Every one knows how, in walking over 

 grassy land, fruits fasten on to the cloth of garments which brush 

 against the plants. If such fruits are examined they will be 

 found to be adapted for dispersal in this fashion. 



The other method by which fruits and seeds are dispersed by 

 animals, especially by birds, affords the explanation of the peculiar- 

 ities of what are known as succulent fruits. In these, part of the 

 fruit, usually of the wall of the ovary, but sometimes the receptacle 

 of the flower or the leaves of the perianth, becomes swollen and 

 when mature soft and succulent. The substance of this is often 

 sweet tasted, and the fruits may also be attractive by their colour 

 or scent. Within the fruit are one or more seeds enclosed in a 

 hard covering ; this may either be the seed-coat or, as in the Plum 

 or Cherry, an inner layer of the wall of the ovary. Space will 

 not permit of a description of the different types of succulent 

 fruits, and this is not necessary in order to understand their use 

 to the plant. Such fruits are adapted to be eaten by birds. 



