324 



FOURTH GROUP.—SEED-PLANTS. 



The male floivers consist of an evidently elongated axis furnished with staminal 

 leaves or sporophylls and terminating above in a naked apex (Fig. 253 A\ exactly 

 similar, for example, to a single sporangiferous spike of Selaginella or Lycopodium. 

 The staminal leaves are usually more delicate than the foliage-leaves and of a different 

 colour, and are generally differentiated into a slender stalk and a peltate lamina 

 which bears the miscrosporangia or pollen-sacs on its under side, as for instance in 

 Ta.\-us. the Cupressineae, and Abietineae (Figs. 252 A, B. 253 A, B, 254 A)\ but 



{ 



VM V 



Fig. 252. Taxus baccata. A male flower 

 magnified ; at a the pollen-sacs. B a stamen from 

 below with the pollen-sacs opened. C a piece of a 

 leafy shoot with a foliage leaf *, and the female 

 flower springing from its axil ; s its envelope of 

 scales, sk the ovule. D longitudinal section of the 

 same magnified ; i the integument, kk nucellus, at 

 X the aborted extremity of the shoot. E longi- 

 tudinal section through an ovule in a more ad- 

 vanced state of development before fertilisation ; 

 ;' integument, kk nucellus, e endosperm, in arillus, 

 s s leaves of the envelope. 



Fig. 253. Juniperus communis. .? longi- 

 tudinal section of the male flower. B a stamen 

 seen from the front and the outside (the upper 

 figure), and one seen from behind and withm 

 (the lower figure). C longitudinal section of the 

 female flower, a denotes the pollen-sacs, s the 

 peltate lamina of the staminal leaf, * lower leaves 

 of the flowering axis, c carpels, sk ovules, kk the 

 nucellus, i the integument. A and C inagn. 

 about 12 times. 



there may be no flat expansion at the end of the stalk, as in Gingko (Fig. 251 C), 

 where it is reduced to a srnall knob from which the pollen-sacs are suspended. That 

 the structures that bear the pollen-sacs in the Coniferae are undoubtedly metamor- 

 phosed leaves is shown by their form, and still more clearly by their position which 

 has been described above and by the history of their development. The pollen-sacs 

 are usually attached by a narrow base to the under side of the support and do not 

 unite together as they grow ; their number is always much smaller than in the 

 Cycadeae and much more variable than in the Angiosperms ; the peltate portion of 



