FRUITS AND SEEDS. 263 



292. Practical Work on Fruits and Seeds. Collect 

 all kinds of fruits, belonging to both wild and cultivated 

 plants, and arrange them according to (1) their structure, 

 (2) their adaptations for seed-dispersal. Make sketches 

 of all the fruits you examine ; cut them across or open them 

 up to make out the structure. Distinguish between one- 

 seeded fruits (akenes, etc.) and true seeds, and notice which 

 part of a fruit is fleshy, which part forms wings or tufts of 

 hairs, etc. Carefully notice and compare the times taken for 

 a winged or plumed fruit or seed to fall to the floor (1) with 

 the wings or plumes still on it, (2) after removing them. 

 Watch the scattering of flattened, winged, and plumed fruits 

 and seeds on a windy day. Why do some winged fruits 

 e.g. Ash- and Sycamore-" keys " whirl round while being 

 blown away, and what are the advantages of this ? 



The structure of small seeds is best made out by the examination of 

 thin sections. Rather puzzling appearances are, however, presented 

 when the embryo is curved or twisted instead of being straight, or 

 when the cotyledons are folded, or divided into lobes, for in such cases 

 the same part may be cut twice in the one section. 



In some seeds special outgrowths or arils are formed at the point of 

 attachment of the seed and funicle, or from the surface of the seed. 

 These assume the form of wartlike, fleshy excrescences in the seeds 

 of the Pansy, Castor Oil plant (Fig. 27), and the Spurge. In the 

 Willow and Poplar the aril is represented by a tuft of hairs which 



frow out from the funicle. Occasionally the aril forms an irregular 

 eshy investment to the seed, an example of which is afforded by the 

 mace of Nutmegs. The succulent part of the red ' ' berry " of the Yew 

 is simply a special kind of aril, as is shown by its mode of development. 



QUESTIONS ON CHAPTER X. 



1. Distinguish between syncarpous and apocarpous fruits, and give 

 examples of common table fruits under both heads. 



2. Compare carefully the flower and fruit of a Rose with those of a 

 Buttercup, and explain, by means of diagrams, the principal differences 

 between them. 



3. Show by comparative drawings of the flower and fruit of the 

 Apple, the Rose, the Blackberry, the Plum, and the Strawberry just 

 what parts of the flower and fruit correspond to one another in each 



