ziH 



MORPHOLOGY OF MEMBERS. 



forming spines, becoming transformed into conical, pointed, hardened bodies. 

 This may take place either by the whole shoot or even a whole branch-system 

 becoming spiny, with suppression of the foliage-leaves, as in the branched spines 

 of Gleditschia ferox, or by the shoot first producing foliage-leaves, growing in the 

 ordinary manner, and finally finishing its growth in length by a spiny point, as 

 in the lower axillary shoots of Gleditschia iriacanthos, Prunus spinosa, and many 

 others. 



Among Phanerogams, especially Monocotyledons and Dicotyledons, displacements of 

 the leaves and lateral shoots (as well as roots), and adhesions of members, constantly occur, 

 which, as development advances, are in apparent contradiction to the typical laws of 

 growth and local position which are the ordinary ones in these classes ; and it appears 



Fig. 157. — Diagram of the adhesion of leaves 

 with the axial parts of their axillary shoots (after 

 Nageli and Schwendener ; Das Mikroskop). 



Fig. \^.—Hermintnnt Monorchis (after T. Irinisch : Biologie 

 und Morphologie der Orchideen. Leipzig- 1853) ; / the lower part 

 of a flowering shoot (natural size) ; //, /// the part containing the 

 bud (magnified). 



impossible to apply even the most general rules of growth which we have now been con- 

 sidering. It would be difficult for even a clever beginner to explain by the principles which 

 have been regarded in this chapter as most universal, the structure, for instance, of the ex- 

 panded flower of an Orchis, Rose, Lamium, Salvia, or of many other plants, of a partially or 

 wholly ripe fig, or the phyllotaxis in the inflorescences of Borragineae and Solanaceae and 

 many others. But the history of development shows that even such cases may be ranged 

 under these laws, and that peculiarities of structures of this kind only arise at a later 

 period, or in such a manner that they confirm general rules. The deviations from these 

 laws are caused by the cessation of the growth of particular parts at an early period, while 

 others undergo a great advance ; or they are caused by the adhesion of parts originally 

 distinct. Although it is quite impossible to give general rules for the explanation 



