ESSENTIAL FLORAL LEAVES. 



93 



an axis upon which numerous stamens are crowded in a spiral 

 manner. They are here more flattened and leaf-like than, for 

 example, in the buttercup, which is a good example of the hemi- 

 cyclic condition. The most typical cyclic flowers possess two 

 whorls of stamens (fig. 38) — an outer, alternating with the petals 

 (and superposed to the sepals), and an inner, alternating with the 

 sepals (and superposed to the petals). As in the case of the 

 perianth, five and four are the typical numbers in a whorl for 

 dicotyledons, and three for monocotyledons. Ten stamens occur 

 in papilionaceous flowers, but the two five-membered whorls are 

 here indistinguishably united together. Fuchsia, willow-herb. 



FIG. 45.— Flowers of Scotch Fir [original]. Various scales. A. Group of 

 male cones. B. A stamen ; ps. pollen sac ; /. filament. C. Pollen grain ; 

 ex. extine; w. wing; r.c.,v.c. cells. D. A female cone. E. An ovule- 

 bearing scale ; ov. ovule ; mp. micropyle. F. A seed. 



and evening primrose possess two whorls of four each, while 

 snowdrops, lilies, and rushes have six stamens in two whorls. 

 Very frequently one whorl is suppressed, usually the inner one. 

 Thus a very large number of dicotyledons are provided with five 

 stamens alternating with the petals, as, for example, in parsnip, 

 disk florets of daisy, potato, violet, convolvulus, and forget-me- 

 not. Others have four similarly placed stamens, as in plantain 

 and verbena. Again, in monocotyledons the outer whorl only 

 may be present, as in iris, where there are three stamens. Far 

 more rarely the outer whorl is suppressed. This is seen in prim- 

 rose and its allies, which possess five stamens superposed to the 

 lobes of the gamopetalous corolla. That a whorl has been here 

 suppressed is proved by the fact that in brookweed or water-pim- 

 pernel, a closely allied plant, rudiments of the outer whorl are 

 actually present. But reduction may go still farther, and leave 

 only part of a whorl. White dead nettle is a case in point. Here 

 there are five sepals and five petals, but only four stamens, two 



