46 

 closed, when, however, the anthers have withered the two 

 styles lengthen and spread apart. 



The Common Cranesbill, {Geranium, macu- 

 latum, L.) is common in woods. The dark 

 lines of the petals converge to the base of the petals where 

 the nectar is found, which is secreted by five glands at the 

 bases of the outer stamens and protected from rain by hairs. 

 The flowers are proterandrous; the five stamens dis- 

 charge their pollen over the center of the flower and after 

 wards the five inner do the same. The anthers commonly 

 drop ofl" before the stigmas expand. Robertson observes 

 that during rainy weather they may be in the male stage for 

 several days, but during warm weather they go through both 

 stages the same day. It is visited by the honey bee, bumble 

 bees, Diptera and some Lepidoptera- Some of the 

 European species have lost all power of self-fertilization. 



Oxalis- Some species of the genus Oxalis are trim- 

 oiphic. Hildebrand found fifty-one species trimorphic. 



Geranium- Our commonly cultivated Geranium 

 {Pelargonium zonale, Willd) colors, various, in many 

 darker zones leading to base of upper petals, these overlap, 

 forming a groove leading down to the nectary, which is 

 made up of the Ijase of one sepal, forming a long narrow 

 tube. Nectar is secreted by the hairs on lower side near the 

 base of this tube. The flowers are proterandrous. The 

 seven stamens mature first, five before the two shorter which 

 occur in front of the opening to the nectar tube. After de- 

 hiscence the pistil lengthens and the style spreads out. The 

 geraniums with us are frequently pollinated by humming 

 birds. 



