PLATANACEAE 375 



openings are made into these spaces through which the pollen falls to be scattered 

 into the air. 



Schonland (Bot. Jahrb., Leipzig, iv, 1883, pp. 308-27) states that hermaphrodite 

 flowers occur now and then. He further observed male flowers with reduced carpels, 

 and female ones with reduced stamens, and also entirely neuter flowers. 



C. ORDER JUGLANDACEAE DC. 



799- Juglans L. 



Flowers anemophilous ; monoecious. Kerner (' Nat. Hist. PI.,' Eng. Ed. i, II, 

 pp. 94, 119, 133, 148) says that the stiff upright spike, which at an early stage is 

 beset with crowded male flowers, elongates before the beginning of anthesis to such 

 an extent that it hangs over and protects the anthers from above with the bracts and 

 perianth leaves. The stamens being now under cover, the anthers dehisce, and the 

 pollen falls into trough-like depressions on the upper sides of the flowers situated just 

 below. It is removed thence in dry weather by gusts of wind. Wamstorf (Schr. 

 natw. Ver., Wernigerode, xi, 1896) says that the numerous little hairs found on the 

 outside of the perianth and the bracts are much more capable of retaining the pollen. 

 The pollen-grains are whitish in colour, irregularly polyhedral, beset with small 

 tubercles, with obvious germinating processes, up to 50 fx. in diameter. Kerner states 

 that the male inflorescences of species of Betula, Corylus, Alnus, and Populus possess 

 the same flower mechanism. 



2562. J. regia L. — Delpino and Darwin {' Forms of Flowers ') describe the trees 

 as partly protogynous, partly protandrous, and the organs which mature first do so 

 a week before the later ones. Kerner says that the species is protogynous, and the 

 female flowers mature 2-3 days before the male ones. 



Delpino ('Ult. oss.,' Atti Soc. ital. sci. nat., Milano, xvii, 1874) states that this 

 is a dimorphous species, not, however, according to the time but to the habitat. 

 Some plants are protogynous in the highest degree, their female flowers maturing 

 about a week before the male ; others are equally protandrous, their male flowers 

 maturing the same length of time before the female ones. There is, therefore, 

 a double pollination and fertilization in two periods, the stigmas of the protogynous 

 plants being pollinated and fertilized about eight days before those of the protandrous 

 ones. The pollen of protandrous plants is transferred to the stigmas of proto- 

 gynous ones by the wind, the stigmas of protandrous plants being dusted with the 

 pollen of protogynous ones by the same means. The numbers of protandrous and 

 protogynous plants are about equal. 



2563. J. cinerea L. — Darwin says that the trees of this North American species 

 also are partly protogynous and partly protandrous. 



CI. ORDER MYRICACEAE RICH. 



800. Myrica L. 



2564. M. Gale L. (Schulz, Ber.D. bot. Ges., Berlin, xi, 1892, p. 409, foot-note; 

 MacLeod, Bot. Jaarb. Dodonaea, Ghent, vi, 1894, pp. 128-9.) — Delpino says that 



