37° PART iy.— VEGETABLE TAXONOMY. 



ones, but they are arranged in a similar manner on the stem. In 

 this respect they show their inferiority to Angiosperms, for in the 

 latter the differentiation between floral and ordinary leaves often 

 extends to the phyllotaxy, the arrangement of the floral leaves 

 frequently being quite different from that of the foliage leaves on 

 the same plant. 



The female flowers vary a good deal in the different species, 

 particularly in the position of the ovules. In some, as the Yews, 

 Fig. 570, B, the flower consists of a naked ovule borne at the 

 apex of a short branch ; in others, as the Spruces, Pines, Larches 

 and Cedars, they form cones consisting of an axis, along which 

 scales or bracts are compactly arranged in spiral order, and in 

 the axil of each bract, and attached to it only at the base, occurs 

 another, which bears on its upper surface two ovules, whose 

 micropyles point downward (see Fig. 571, A) ; the Araucarias of 

 the Southern hemisphere have flowers of similar structure, except 

 that the carpellary scale is completely fused with the bract, in 

 whose axil it is borne ; in the Taxodiums, represented by the 

 Bald Cypress of our Southern States, the fusion between carpel- 

 lary scale and subtending bract, has also taken place, but the 

 micropyle of the ovule is directed upward instead of downward ; 

 and in the Cupressinese, to which belong the Juniper, Savin, 

 Red Cedar and Arbor Vitse, the carpellary scale is completely 

 fused with the bract, the mycropyle of the ovule is directed 

 upward, and the bracts are arranged on the axis in whorls instead 

 of spirals. By some botanists the cone is regarded as an inflor- 

 escence or flower-cluster ; by others as a single flower. 



For illustrating more particularly the mode of reproduction 

 in this group, we may take the Scotch Fir, Pinus sylvestris. This 

 species is monoecious, and the staminate flowers are borne in 

 clusters on the lower parts of shoots of the same season. Each 

 scale produces two pollen-sacs placed longitudinally, side by 

 side, on the lower surface. The pollen-grains when ripe consist 

 of a central body with two vesicular, wing-like appendages, as is 

 frequently the case with the pollen of Coniferse. The body of the 

 grain, or the pollen-grain proper, consists of two cells, a smaller 

 vegetative one, representing a prothallium, and a larger one, 

 which corresponds to that in the microspore of Selaginella, 

 which produces antherozoids, but which here, in germinating, 



