116 



PLANT STUDIES 



reports of ''showers of sulplnir" have 

 arisen from an especially heavy fall of 



1 1 \ pollen that has lieeii carried far from 



\ \ 

 ,, ,, V ,\ some gymnosperm forest. In the ease 



• /( '' hV 1^1 ^^ pines and their near relatives, tlie 



/^IjiW ^f"h#(\l Pollt^n spores are assisted in their dis- 



/ /s^M '////l)ll; pei'sal thri)Ugli the air hy developing a 



pair of broad wings from the outer 



// \t( 'v v'[ ^'"'^* °^ ^^^^ '"1^^"'® (^^'^ ^^^' -""'• '^'^'^^ 



\''(/ "A^ same method of jioUinatien — that is, 



carrying the jiollcn sjiores hy currents 



Fic. ns \\'hi.'.-ci iriiitdf "^ ''i-' — i^ -'Iso used l.)y )ua.nv mcno- 

 Ai/,ni//ius.~AHnKEi'.- cotvledous, sucli as grasses ; and hy 

 man_v dicotyledons, such as our most 



conimon ferest trees 



(oiik, hickdi'y, chest- 



nul, etc.). 



7x. Dispersal of 



seeds by air. — Seeds 



are \'(!ry rarely light 



enough to he (tarried 



liy cui'rcnis of air 



without sonic s})eeial 



:i,(hiptn,t i(.)ii. Wings 



and ]iliiiiics of very 



nia.MV and often very 



hea II I i fill ])at terns 



ari' exceedingly com- 

 mon in connection 



witli seeds or seed- 

 like fruits (see Figs. 



115, 11 li, II r, lis, 



Il!l). \\'iiigs arc de- 

 veloped liv the fruit 



of maples and of 



1 1 i). Fig, 111). Fruit of l.ufswooil (7'i/ia), shdwing the 



asll, and Ijy the seeds peculiar wiug formcJ by a leaf.— Aftxr Kerneu. 



