CHAPTER XXVI 



ROSACEA (Rose Family) 



The Rosaceae are well represented in North Temperate 

 climates. There are about 1,200 species within 65 genera. 

 The most important genera from the crop standpoint are 

 Rubus (raspberry, blackberry and dewberry), and Fragaria 

 (strawberry). Other genera of importance or of interest are 

 Spircea, an ornamental shrub, Potentilla (five-finger or cinque- 

 foil), Cercocarpus (mountain mahogany), and Rosa (rose). 



Leaves. — The leaves are alternate, either simple (as in 

 some Rubus species), or compound (strawberry, rose). 

 There are two rather prominent stipules, free from or adher- 

 ent to the petiole. 



Inflorescence.— There are several different kinds of flower 



clusters in the family. It is a terminal corymb (flat-topped 



raceme) in Opulaster, either racemose, 



cymose, corymbose or paniculate in Spircea, 



terminal or axillary and solitary, racemose 



or paniculate in Rubus, and corymbose or 



racemose in the strawberry. It is interest- 



FiG. 146.— Floral i^g to note the great number of different 



diagram of Rubus. gQ^jg gf inflorescences in this one family, and 



(After Wossidlo.) , •' ' 



contrast it with the mustard family, in which 

 the raceme is the one prevailing type, or with the carrot 

 family in which the umbel is, . with the exception of one 

 genus, the only type, or with the sunflower family, all mem- 

 bers of which have a head inflorescence. 



Flowers. — The flowers (Fig. 146) are regular, and usually 

 perfect. In some cultivated strawberries imperfect flowers 



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