ORGANS OF REPRODUCTION. 



181 



leaf-buds in their axils. In some cases the non-development of 

 flower-buds in the axil of bracts appears to arise simply from 



Fig. 369. 



Fig. 370. 



Fig. 368. Flowering stalk of the Pirapemel 

 (AnagaUisarvensis). b, b. Solitaryflowers 

 arising from the axil of the leafy bracts, 



a,n. Fig.SQQ. Flower of Marsh-ilallow 



(Althcea officinalis) surrounded by an epi- 



calyx or involucre. Fig. 370. Flower 



of Strawberry (Fragaria vesca), sur- 

 rounded by an epicalyx or involucre. 



causes ; but in others, it 

 a regular law, thus in the 



accidental 

 occurs as 



Purple Clary (Salvia Horminum) and 

 the common Pine-apple {fig. 266), 

 there are a number of bracts without 

 flower-buds placed at the apex of 

 the inflorescence. Bracts from which 

 flower-buds do not arise are called 

 empty. When bracts are absent al- 

 together, as is usually the case in the 

 plants of the natural order Cruciferse, 

 and in the Boraginacese, such plants 

 are said to be ehracteated ; when bracts are present the in- 

 florescence is said to be hracteated. 



Bracts follow the same law of arrangement as true leaves, 

 being opposite, alternate, or whorled, &c., in different plants. 

 The bracts of the Pine-apple fruit {jig. 266), and those of Fir 

 cones {figs. 267 and 394), show in a marked manner a spiral 

 arrangement. 



Bracts vary in their duration ; when they fall immediately, or 

 soon after the flower-bud expands, they are said to be deciduous. 

 When they remain long imited to the floral axis, they are persis- 

 tent. In some plants, they remain and form a part of the fruit ; 

 thus, in the Nut and Filbert they form the husk {fig. 375), in 

 the Acorn they constitute the cup {fig. 37-t), and in the Hop- 

 fruit {fig. 395), in the Fir-cones {figs. 267 and 394), and Pine- 

 apple {fig. 266), they persist as membranous, woody, or fleshy 

 scaly appendages. 



