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THE POPULAR SCIENCE MONTHLY. 



appear, until finally there would remain a single one of much, 

 increased serviceableness (Figs. 18 and 19). 



3. For the reasons already given we may suppose the sta- 

 mens to have their anthers so modified as to open by hinged 

 valves,* while at the same time there was developed upon each 

 filament a pair of nectar glands (Fig. 18). Insect visitors, finding 

 an abundance of nectar in a flower, would be less likely to feed 

 upon the pollen, which is so precious to the plant. As the posi- 

 tion of the nectar is nearer the center of 

 the flower, the visitor comes to occupy a 

 more definite place relative to the pistil 

 and stamens. The six stamens of the inner 

 row are for the most part the only ones 

 which can have their anthers touched, for, 

 as will be seen from the diagram, the re- 

 mainder are so placed as to be directly 

 behind the others. Being thus superflu- 

 ous as pollen- producers, the anthers of 

 the other stamens would naturally degen- 

 erate, and if they follow the general rule 

 of stamens in flowers which are provided 

 with an abundance of building material 

 (as, for example, the " double " flowers of 

 the florists), they would change into some- 

 thing very like petals. If these petaloid organs became slightly 

 arched over the inner stamens, they might still be of use in the 

 floral household by giving better protection to the pollen than 

 it had previously had, and at the same time increase somewhat 

 the conspicuousness of the blossom. While it is by no means 

 clear that any advantage is gained by having such an organ 

 bilobed at the upper end, it might be a not unnatural result of 

 that special part's having been derived from a bilobed anther. 

 A glance at Figs. 3 and 16 will show that just such a petaloid 

 organ is situated behind each of the stamens in a barberry flower, f 



Fig. 19. Diagram of euberberis 

 flower. Bracts and sepals as 

 before ; petals, six, with nec- 

 tar glands ; stamens, six, with 

 valves but no glands ; carpel, 

 one ; ovules, few. 



* If it be supposed that the flowers were originally erect, it is possible that this pecul- 

 iar modification of the dehiscence may have arisen as a protection against rain, which 

 would thus be hindered from washing away the pollen, or indeed quite prevented from so 

 doing if the valve could have had that power of closing in wet weather and opening in 

 dry which Kerner ascribes (Pflanzenleben, p. 123) to the anther valves of certain Lauracece. 

 At the present day, as we have seen, the barberry stamens are so well shielded from the 

 rain by the pendent attitude of the flowers that any such peculiarities of the anthers can 

 hardly be of much service in this particular. Still, the assumption that this was equally 

 true in the ancestral forms is of course unwarranted. 



f In B. vuk/aris it is the rule for these petals to be entire, its near relative, B. canadoisis, 

 having them bilobed. Fig. 3 and also Fig. 16 were, however, drawn directly from un- 

 doubted specimens of B. vulgaris. 



