VI] RANUNCULUS: HELIOPSIS 51 



B, slightly older stage showing the inception of the first five stamens a, 

 somewhat higher up on the dome and alternating with the petals ; better 

 seen in C, the same stage viewed laterally. D, an older stage, from the 

 side, showing the development of more stamens a, in acropetal succes- 

 sion, followed by the youngest incepts of carpels g, still higher up the 

 flanks of the dome. E, still more advanced stage ; the carpels g are now 

 formed in acropetal succession all over the dome, and the stamens a, 

 petals c, and sepals k, are approaching completion. F, carpels from the last 

 figure, seen from above and more highly magnified, showing the infolding 

 of the margins. G, the same from the side, and H from above, still more 

 advanced and enlarged; the single ovule o is arising from the antero- 

 basal placenta, and the margins are closing in over it. J", a mature carpel 

 in longitudinal section, showing the ovule in position (P). 



In some flowers, moreover, the order of succession of 

 the various parts becomes altered from what we should 

 expect it to be. 



After these preliminary matters, we may now examine 

 a few cases in illustration of these and other peculiarities 

 of the development of the flower. 



In the figure on p. 50 (Fig. 15) A shows the highly- 

 magnified apex of a young Buttercup viewed from above. 

 We see an apical dome of embryonic tissue with 10 lateral 

 protuberances, of which k' is the oldest and lowest of 

 what will be the sepals, while k" k'"" are next in order 

 of succession. Then follow the still smaller and younger 

 petals c, still in the condition of mere incepts. 



In the next stage, Fig. 14, B and C, we find the stamens 

 arising as minute lateral outgrowths (a) somewhat higher 

 up the still growing central dome; and later on (Figs. 

 I) and E) more and more lateral outgrowths are produced 

 to form the remainder of the stamens (a) and the 

 carpels (g). 



In contrast to this example, where the floral organs 

 arise in their natural sequence on the sides of the dome, 

 we may examine the development of Heliopsis, one of the 

 Composite. 



42 



