FRUCTIFICATION; PROTECTION OF FRUITS. 



47 



always are all of the ovnriaii wails in- an outgrowth from the ovary itsi'lf. as in 



■m 



volved in the development, A gynaerium Stramonium (Fig. 240), sometimes upon 



an enclosing calyx (Fig. 241), an enclosing 

 wall, consisting of a hollowed branch, vs 

 in the prickly i^ear (Fig. 242), or some- 



possessing several pistils may fail to de- 

 velop all of them in fruit (Fig. 1S5), and 

 when these are adnate into a conipt.nnd 

 ovary, as in Vallesia, one or more of them 

 may likewise fail to develop. A several- 

 celled ovary, as in Calesinm (Fig. 239a), 



Fig^'*'*- 



Tiq Z'il 



'-• a-*5; 



times upon an enclosing involucre, as in 

 the chestnut burr (Fig. 243). At other 

 times the protection is secured by devel- 

 oping acrid or otherwise disagreeable peri- 

 carps, as the husk of the walnut or the 

 pulp of the colocynth. These defences 

 may be effective only during the maturing 

 stage, as already pointed out, or their 

 deterrent action may be permanent. In 

 the same direction are to be considered 

 the effect of poisonous principles proper 

 and the inedible nature of the pericarp 

 pending the maturing of the seeds. 



The transfer of the fruit to the ph^ce of 

 germination is secured by methods which 

 for the most part admit of classification. 

 We shall first consider those provisions 

 which utilize the agency of the wind for 

 this purpose. 



We note, first, that the weight of fruits 

 to be thus transported is reduced to a 

 minimum. They are iii almost all cases 

 one-seeded (Monospermous), the loss due 

 to this character being made good by the 

 fructification of a large number of flowers. 



may^, after the fertilization of one or The one-seeded condition of such fruits is^ 



aiore ovules in une or more cells, permit 



the abortion of those in the other cells, the 



septa of the latter being then crowded 



against the outer wall by the growing 



seeds, or even disappearing, so that the 



fruit will contain u smaller number of 



cells than the ovary which produced it. 

 The partial obliteration of cells in a sim- 

 ilar manner is well shown in the fruit of 

 Diospyros (Fig. 239b). Additional walls 

 ui>on the other hand, may develop during 

 fructification. Datura has a 2-celled 

 ovary (Fig. 240a), but a 4-celled fruit 

 (Fig. 240), and this occurs regularly in 

 the Labiatae. The newly formed walls 



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F.g 3*, 



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,.-*'**-s- 



C\. .■^:.y:fc-^-. 



Fig asa. 



are not always vertical. 



The 



fruit of 



Desmodium (Fig. 301 a) and that of So- 



phora (Fig. 301) divide transversely into 



one-seeded joints. 

 Concerning the protection of the fruit 



and seeds we note that its full accomplish- 

 ment often calls for other detViusivf pro- 

 visions than those against merely mechan- 

 ical forces, in the form of appendages con- 

 stituting an armor. These are sometimes 



•'■r IV^^?. 



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n^zii 



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moreover, not restricted to families which 

 are characterized by it. Many fruits of 

 the Leguminosaej which are commonly 

 several or many-seeded, as the pea and 

 bean, become one-seeded when adapted ^o 

 wind transportation iFigs. 244 and 245). 

 Fruits whieh are not one-seeded may di- 

 vide into one-seeded i)arts, easily separa- 



