468 



PHANEROGAMS. 



manner that the apex of the axis is placed at the bottom of the hollow {cf. Fig. 152, 

 p. 200), while the cup thus formed encloses the carpels (as in perigynous flowers), 

 or even takes part in the formation of the ovary, which is then inferior (Fig. 328). 

 But in every case, owing to the abbreviation of the axis, the separate parts do not 

 usually stand one above another, but rather in concentric whorls, or in scarcely 

 ascending spirals, for which reason the explanation of the relative positions expressed 

 by a diagram in the sense explained on p. 167 appears the most obvious. This 

 abbreviation of the axis is also obviously the immediate cause of the numerous 

 cohesions and displacements which are nowhere met with so frequently as in the 

 flowers of Angiosperms. The small development of the floral axis in length depends 

 on the early cessation of its apical growth ; the acropetal or centripetal order of suc- 

 cession of the floral leaves may therefore be disturbed^ by the production of inter- 

 calary zones of growth, although even in these cases the disturbance of the ordinary 

 regularity remains inconsiderable. The acropetal order of succession is however 

 even here in most cases strictly carried out, and the apical growth of the floral 



FlG.328.—^sarit7/! ctnadense; .-/ tlie flower cut through lengthwise, / the perianth; ^ horizontal section of the 

 flower above the ovary; C horizontal section of the sex-locular ovary ; D a stamen with its lateral anther-lobes a. 



axis not unfrequently continues long enough to allow the foliar structures to arrange 

 themselves in evident whorls placed one over another or in spirals (e.g. Magnolia, 

 Ranunculaceae, Nymphseaceae). Occasionally also particular portions of the axis 

 are greatly elongated within the flower, as the portion between calyx and corolla in 

 Lychnis (Fig. 330 dis, p. 472), in Passiflora that between corolla and stamens, in 

 Labiatse that between stamens and ovary. 



The flower of Angiosperms, like that of Gymnosperms, is a metamorphosed 

 shoot, a leaf-bearing axis; but this section of the vegetable kingdom is especially 

 characterised by the high degree of metamorphosis which the floral shoot has 

 undergone, and by the very peculiar characteristics and the diff'erent arrangement 

 of the foliar structures as contrasted with those of the purely vegetative shoots- 

 As far as external appearance goes, the flower of Angiosperms is an altogether 

 peculiar structure, sharply differentiated as a whole from the rest of the organism. 

 This peculiar appearance is due not only to the special properties of its axis, 



' The cases adduced by Hofmeister (Allgemeine Morphologic, § 10) of the absence of strict 

 acropetal succession in the foliar structures all belong to this category. 



