DEVELOPMENT OF PLANTS 407 



in probing for the nectar is sure to receive some of the sticky 

 microspores on his body. Each day, for about a week, succes- 

 sive series of stamens behave in this manner, and it is not until 

 the innermost anthers are discharging on the last day of bloom- 

 ing of the flower that there is an opportunity for autogamy. In 

 man}' members of this and other orders you will find that the 

 stigmas and anthers of the innermost stamens actually meet, 

 owing to the peculiar curvature of the styles and filaments, thus 

 ensuring autogamy in case crossing has failed. It should be 

 borne in mind that the devices for effecting autogamy, as a last 

 resort, are quite as general and often as elaborate as the pro- 

 visions for bringing about crossing. The microspores are pro- 

 tected against dews and rains by the folding of the perianth and 

 also by the downward curvature of the pedicel at night, while on 

 each succeeding bright day the perianth opens again and the 

 flower becomes nearly or quite erect and turned towards the 

 light, so that it is in a position from which the insect will naturally 

 come. The opening of the flower is due to a growth in the morn- 

 ing of the basal, inner portion of the petals which bends them 

 away from the center of the flower, thus opening the flower ; 

 while a corresponding growth towards evening of the basal outer 

 part of the petal bends them towards the center of the flower. 

 This growth slowly increases the size of the flowers, as may read- 

 ily be observed by comparing the freshly opened flowers of the 

 anemone, buttercup, etc., with those several days old. All these 

 features are of common occurrence in a great variety of orders. 

 The fruit of the buttercup is an akene, each carpel containing but 

 a single ovule (Figs. 305, E; 261 B). 



(b) Some Variations of the Order. — Many variations of this 

 simple structure appear in other members of the order. The 

 carpels may be reduced to one, as in sassafras and other groups, 

 and in the green hellebore (Fig. 306, A) they are partially fused 

 and even united with the receptacle in some water lilies, etc. 

 (flowers perigynous and epigynous). The stamens are some- 

 times few in number and they are frequently modified into nectar 

 glands and assume a variety of odd shapes (Fig. 306, A). The 

 showy nectar-bearing petals, honey leaves, of many of the genera 



