108 CARPOLOGY: FUNCTIONS AND STRUCTURE OF THE FRUIT 



classification. We shall first consider those provisions which utilize 

 the agency of the wind for this purpose. 



Transportation by the Wind. — We note, first, that the weight of fruits 

 to be thus transported is reduced to a minimum. They are in almost 

 all cases one-seeded (Monospermous), the loss due to this character 

 being made good by the fructification of a large number of flowers. 

 The one-seeded condition of such fruits is not restricted to families 

 which are characterized by it. Many fruits of the Leguminosae, which 

 are commonly several- or many-seeded, as the pea and bean, become 

 one-seeded when adapted to wind-transportation (Figs. 296 and 299). 

 Fruits which are not one-seeded may divide into one-seeded parts, 

 easily separable, to facilitate transportation by wind or other agencies, 

 as has already been shown. 



Morphology of Fruit-wings.— Such a state having been attained, the 

 action of the wind upon them is next secured through the development 

 of an expanded surface of some kind, commonly a wing or plume. 

 In the Platypodium (Fig. 296) it is the entire wall of the ovary, in its 

 original nature a pod, like that of the bean, which becomes developed 

 into a wing. In the elm (Fig. 287) it is likewise the ovarian wall. In 

 the carrot (Fig. 288) and the Rumex (Fig. 289) it is an enclosing accres- 

 cent calyx. In the Piptoptera (Fig. 290) it is two accrescent lobes of 

 such a calyx. In the Zinnia (Fig. 291) a persistent corolla performs 

 the same office. In the hop (Fig. 292) an accrescent bract is made to 

 serve the office of a sail. The fruit of the Cardiospermum (Fig. 294) 

 represents a class in which the thin pericarp, instead of being expanded 

 into a wing, is inflated into a balloon-shaped receptacle, subserving a 

 similar purpose. Plumes, consisting of the modified persistent calyx, 

 are seen in the Valerian (Fig. 293) where it is present, though concealed 

 by a circinate praefloration, from the flowering stage, while in the 

 Phyllactis it is not developed until after fructification begins. A 

 plumose style is seen in Pulsatilla (Fig. 286). 



Transportation by Attachments. — We shall next note the cases, per- 

 haps even more numerous, wherein use is made of passing bodies by 

 providing such appendages as shall serve to attach the fruit to them. 

 Fig. 298 represents the fruit of a Rumex, in which the calyx is divided 

 into hooks for this purpose. Fig. 297 shows another species, in which 

 this method is combined with wind transportation, a combination which 

 is very common among the Umbelliferae. The accrescent calyx teeth 

 (awns) of Verbesina (Fig. 295) are adapted to piercing passing bodies, 

 while at the same time the adnate tube is winged. In Bidens (Fig. 300) 



