5?>^ 



PHANEROGAMS. 



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. 358). The result of 

 this abbreviation of the axis is that 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. 188 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 succession of the floral leaves may 

 therefore be disturbed ^ by the production of intercalary 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 axis not unfrequently continues long enough 



hAJ. 



Fig. se,g.—CheHOJ'ocitum Quinoa; /—/^development of the flower (in longitudinal section), /the calyx furnished 

 with glandular hairs h, a anthers, k, k carpels, sk ovule, x apex of the floral axis, V horizontal section of an anther 

 with four pollen-sacs on the connective on (strongly magnified). 



to allow the foliar structures to arrange themselves in evident whorls placed one over 

 another or in spirals {e.g. Magnolia, Ranunculaceae, Nymphaeaceae). Occasionally 

 also particular portions of the axis are greatly elongated within the flower, as the 

 portion between calyx and corolla in Lychnis (Fig. 361), 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 different 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 



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

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



