1540 A TEXTBOOK OF THEORETICAL BOTANY 



the fruit. Normally it encloses only one seed, which has a thin, 

 papery testa, the endocarp giving all the protection needed. The 

 only drupes which possess more than one stone, with rare 

 exceptions [Ilex aqiiifolium), are those formed from inferior 

 ovaries, which are classed among the pseudocarps, the stones 

 being, in fact, akene fruits. In the fruits mentioned above, the 

 mesocarp is soft and edible, except in the Almond, itself the 

 endocarp, where the rather hard, green mesocarp splits open 

 to reveal the stone. Some of these hard stones present diffi- 

 culties at germination, which we shall touch upon later. The 

 mesocarp may contain an abundance of fibrous tissue and 

 in such cases the soft parts may disappear at maturity, leaving 

 a purely fibrous mesocarp. Drupe fruits are common among the 

 Palms, and many of them are of this fibrous type, notably the 

 Coconut (Fig. 1404). The "nut" here is the seed covered by 

 the endocarp, which is enclosed in a massive fibrous mesocarp 

 and this in turn by a leathery epicarp, the whole fruit being 

 about twice the size of the nut. The resistance of the Coconut 

 to salt water is chiefly shown by the complete fruit, which can 

 float unharmed for a considerable time, while the nut itself soon 

 decays in the sea. The fibre is the coir or coconut fibre of com- 

 merce. Another Palm with a fibrous mesocarp is Ntpa, which, 

 like Cocos, grows close to the sea, often in brackish swamps. 



III. Pseudocarps or " False Fruits " 



The examples of the class of fruits, generally distinguished by this title, 

 are only a few of the most striking. Many others equally eligible for 

 inclusion are, as we have seen above, neglected because they present no 

 prominent diflFerence from other related types. The strict criterion is that 

 a pseudocarp includes structures other than the gynoecium, but, as we 

 have already argued, all the structures in a fruit, of whatever origin, are 

 integrated to form a biological unit, even if it is not morphologically 

 homogeneous. 



The first examples in this class are the Apple and the Pear, which come 

 from inferior ovaries. The five central carpels have thin cartilaginous walls, 

 enclosing the seeds. The external flesh must necessarily include other floral 

 tissue, which may be interpretable as either a hollowed floral receptacle or 

 a sheath of concrescent sepal, petal and stamen bases. This question we 

 have already gone into (see p. 1219). It is probable, however, that the 

 cartilaginous wall is really an endocarp and that some part o*^ the outer 

 flesh is truly mesocarp. Indeed a cleavage may sometimes develop medianly 

 in the flesh, separating an outer portion and an inner, five-lobed portion, 

 which lends support to this view. These fruits and related types, like the 

 Quince, are called pomes (Fig. 1402). 



The Rose fruit or " hip " is somewhat similar to the pomes except 

 that the surrounding tissue is not united to the enclosed carpels, a cluster 



