POLLINATION 173 



Anemophily characterizes the Betulaceae, Fagaceae (part), Juglanda- 

 ceae, Urticaceae, Casuarinaceae, Gramineae, Cyperaceae, Ulmaceae, 

 Restionaceae, Plantaginaceae, Saururaceae, Juncaceae (part), Amaran- 

 thaceae (part), isolated genera in other famihes — Artemisia, Ambrosia, 

 and Xanthium in the Compositae, Fraxinus in the Oleaceae, Thalictntm 

 and Cimicifuga in the Ranunculaceae, Sanguisorha and Acaena in the 

 Rosaceae, Mercurialis in the Euphorbiaceae, Rtimex in the Polygonaceae. 

 From this hst, it is clear that anemophily is distributed throughout the 

 angiosperm system and in taxa that are highly specialized, not primitive. 

 In these taxa, the flowers are mostly numerous, small, inconspicuous, 

 and odorless, with perianth absent or greatly reduced, not brightly col- 

 ored. Other features of flower and inflorescence structure that occur 

 frequently in anemophilous taxa are flexuous staminate inflorescences — 

 many Amentiferae; greatly elongate and flexuous pedicels of staminate 

 flowers — species of Acer; elongate filaments with versatile anthers — 

 grasses and sedges, many Restionaceae, TJialictriim, Plantago. The genus 

 Acer shows, in its staminate flowers, a series in loss of perianth, nec- 

 taries, and odor, and in elongation of pedicles accompanying the change 

 from entomophily to anemophily. Species like A. riibrum and A. sac- 

 charinum with subsessile flowers, corolla, and odor are entomophilous; 

 A. saccharitm, and A. Ncgundo with long pedicels and naked, odorless 

 flowers are anemophilous; other species show transitional stages. Explo- 

 sive deliiscence, especially the simultaneous dehiscence in many flowers, 

 as in some Urticaceae, is accessory to wind pollination. Some of the 

 Amentiferae, a chiefly anemophilous group, are apparently in transi- 

 tion from entomophily to anemophily. In the Salicaceae, Salix has showy 

 stamens, well-marked vestigial perianth parts, serving as nectar-secreting 

 glands, and pollination is partly by wind and partly by bees; Popnltis is 

 strictly wind-pollinated, without nectar secretion, and has inconspicuous 

 stamens. In the dominantly wind-pollinated Fagaceae, 60 per cent of 

 the insect visitors of Castanea (C. sativa) are beetles. 



In entomophilous plants, transfer of pollen by beetles is apparently 

 primitive; that by bees, butterflies, moths, and flies, is later acquired. 

 Insect pollination may be secondarily acquired from wind pollination, 

 as is apparently the condition in Ficiis, Euphorbia, Hevea, Ricinus, the 

 Nyctaginaceae, and in some of the Araceae. It is phylogenetically signif- 

 icant that beetles, primitive insects, are associated with the primitive 

 Eupomatiaceae and Calycanthaceae to the exclusion of other insects, 

 and with the also primitive Magnolia, lUiciiim, Poeonia, and the Nym- 

 phaeaceae, where they seem to play the major part in pollination. The 

 association strongly supports the now generally accepted view that the 

 woody Ranales are the most primitive living angiosperms. It is evidence 

 that the angiosperms were well established and probably diverse before 



