SEED-PLANTS. 303 



of the very smallest amount ; in the Angiosperms on the contrary it is the rule that 

 the axil of every vegetative leaf, that is, of every leaf which does not form part of a 

 flower, produces a lateral shoot and sometimes more than one beside and above one 

 another, though the buds when formed often remain inactive or develope only in later 

 years. Besides the cases of probable dichotomy mentioned above, it is only in the 

 Angiosperms that we meet with instances of real or apparent extra-axillary branching, 

 and these will be noticed again under that division. 



The Phanerogams are distinguished from the Vascular Cryptogams by an 

 unusually varied and far-reaching metamorphosis of morphologically similar members, 

 and this difference is correlated with an endless variety in the mode of life, a strict 

 division of labour in respect to the physiological functions of these plants, and also 

 with a greater differentiation of tissues than is to be found even in the Ferns. In 

 these respects, as in others, the Gymnosperms occupy an intermediate position 

 between the Vascular Cryptogams and the other Phanerogams. 



The remarks which have now been made have given a general view both of the 

 differences between Vascular Cryptogams and Phanerogams and also of their points 

 of agreement and their mutual affinity. But to make the descriptions which will be 

 given below of the characteristics of the different classes of Phanerogams more easy 

 to understand, it will be well first of all to make some further mention of certain 

 peculiar features in them, which were only briefly touched upon above, and to 

 endeavour to settle the nomenclature which is to some extent antiquated and in many 

 cases unsuitable to modern views. 



The flower in the widest sense of the word is formed from the sporophylls^ and from 

 the axis that bears them ; if the leaves on the same axis immediately beneath the 

 sporophylls are different from the other leaves of the plant in position, form, colour or 

 structure, and have a functional connection with fertilisation and its consequences, they 

 are considered as forming part of the flower and are termed the floral envelope or 

 perianth. The single flower contains only one axis with its sporophylls and perianth- 

 leaves, and thus differs from the inflorescence which is a system of axes with several 

 flowers *. The whole body of male sporophylls in a flower has been named by Roper 

 the androecium, that of the female the gynaeceum. If a flower has both kinds of 

 sporophylls, it is said to be bisexual or hermaphrodite ; if the flowers of a plant contain 

 only male or only female sporophylls, they are unisexual and are called diclinous ; if 

 the diclinous flowers are found on the same plant, the plant is said to be monoeciotts, 

 if on different individuals only, the species is dioecious. Usually growth ceases at the 

 apex of the flowering axis as soon as the formation of the sporophylls begins, and . 

 sometimes even sooner ; the apex of the axis is then concealed and often lies deep 

 down in the centre of the flower ; in abnormal cases, but normally in Cycas, apical 

 growth begins afresh in the flowering axis, and leaves are again produced and some- 

 times even a new flower ; in this way proliflcation of the flower takes place. The 

 sporophylls and perianth-leaves are usually placed close together, forming rosettes 

 or arranged in whorls or spirals ; the portion of the axis which bears them remains 

 very short and usually no internodes can be distinguished in it, and sometimes it 

 becomes club-shaped or forms a flat expansion or is hollowed out. This part of the 

 flowering axis is termed the toriis ; in the Coniferae and Cycadeae, and in some 

 Angiosperms also, it may be so elongated that the sporophylls appear to be arranged 



1 This and all similar definitions may still leave it difficult to distinguish in some cases between 

 a flower and an inflorescence ; the Euphorbiaceae, for instance, have given rise to controversy on this 

 point. 



