432 MORPHOLOGY. 



of the individual parts of the pistil depend almost solely upon the 

 healthy development of the embryo. Hence those cells in which 

 no seed-buds are developed to seed are in like manner arrested in 

 their development, and in the matured fruit are scarcely to be 

 recognised. This non-development of some of the cells appears to 

 be as it were the normal rule in some plants : thus, in many Palms, 

 e. g. Chamcedorea, of three cells one only is commonly developed, 

 whilst the others dwindle away. The same occurs in all Cupuliferce; 

 and the germen of Castanea, with six cells and twelve seed-buds, 

 usually produces a one-celled, one- seeded fruit. In the ripe 

 fruit, therefore, it is always impossible to determine the original 

 number of cells and seed-buds. On the other hand, large air- 

 cavities are not un frequently formed in the wall of the germen, 

 which assume the deceptive appearance of natural cells containing 

 no seeds, as in Nigella. 



Another important matter, moreover, is the development of 

 cellular tissue from the inside of the wall of the cavity of the 

 germen, by which are not unfrequently formed, in long germens 

 (but always subsequent to the origin of the embryo), false septa, 

 which are transverse, and therefore have a direction in which true 

 septa never can occur. The general term for fruits with these false 

 septa is a lomentum; examples of it occur in Raphanus and Orni- 

 thopus. Sometimes this cellular tissue, instead of forming actual 

 false septa, is accumulated thickly between and around the seeds 

 filling the cavity, as in Glaucium, Ceratonia, &c. 



The conditions of structure of the germen are here to be parti- 

 cularly kept in view. 



Through the entire range of Phanerogamic plants, we find the 

 most diversified metamorphoses in the structure of the germen ; on 

 account of which the ripe fruit presents a great multitude of 

 different appearances. So far as my observations extend, two dif- 

 ferent types may be distinguished in the development, according as 

 the layers of cellular tissue of the testa become tougher and firmer 

 from within outwards or from without inwards. In the former, be 

 the morphological import what it may, four several cell-layers are 

 universally to be distinguished, although they sometimes appear 

 more clearly than at others ; namely, the epidermis of the outer 

 surface ; the epithelium of the inner surface ; and between the two 

 an external parenchymatous layer, the cells of which are generally 

 delicate-walled, fleshy, and of simple polyhedral form ; and, finally, 

 of an inner parenchymatous layer, the cells of which are more or 

 less thick, coriaceous, or woody, and always elongated. 



The second type is exhibited in those fruits in which the paren- 

 chyma is developed more or less fleshy and succulent, and frequently 

 toward the interior, where it bounds the fruit-cavity, broken up into 

 isolated cells ; whilst either only the epidermis of the outer surface 

 is very thick, or else some layers of cells thicken beneath it ( Cucur- 

 bitacece), or sometimes acquire even a woody texture (e. g. La- 

 genaria and Crescentia). In the mass of isolated, juicy cells which 



