97 

 appear, as is usual with anemophilous plants. They have 

 an abundance of nectar, " which , in the early flowering 

 periods, leads many insects to go to it. They also have a 

 decided odor. The staminate flowers are more conspicuou.^ 

 than the pistillate, especially in 8alix nigra. 



Each flower consists of a small bract, with the sta- 

 mens, one or more, to the inside. These are accompanied 

 by one or two small nectar glands. In the pistillate flower 

 the stamens are replaced by the pistil and a nectar gland. 

 The willow is one of the lowest of the entomophilous plants. 

 It is visited by a variety of insects. The honey bee, bumble 

 bee Andrena, and other Hymenoptera visit it, as also do 

 flies {BombyliuH), butterflies ( Vanessa), and beetles. The 

 Andrnas are common visitors; the head and thorax of 

 these insects are provided with hairs and as the insects take 

 the nectar from the staminate flowers the pollen grains ad- 

 here tu the bristles and then as they go to the pistillate 

 flowers for nectar some of the pollen is left on the stigma. 

 The petioles of some of our willows are provided with 

 glands. Salix laurifolia has so many of these glands 

 that the tree has a decided odor. These glands are no doubt 

 for protection. 



Darwin, in the introduction to his classic 

 Orcliidaceae. 



work, "On the Fertilization of Orchids by 



Insects" says: "As orchards are universally acknowledged 

 to rank amongst the most singular and most modified forms 

 in the vegetable kingdom, I have thought that the facts to 

 be given might lead some observers to look more curiously 

 into the hadits of our several native species. An examina- 

 tion of their many beautiful contrivances will exalt the 

 whole vegetable kingdom in most persons' estimation." 



Earlier Sprengel observed that insects were necessary to 



