POMACES 367 



Geographical. — The family is of wide geographical distribution, there being 

 close to 22s species within about 20 genera. Most of the species occur in 

 north temperate or boreal regions. 



K.EY TO Important Genera of Pomaces 



Ripe carpels bony, Cralagus (thorn-apple, haw, hawthorn). 

 Ripe carpels papery or leathery. 

 Leaves compound, Sorbus (mountain ash). 

 Leaves simple. 



Ovules one in each cavity, Amel^nchier (service-berry, June-berry). 

 Ovules (usually) two in each cavity. 

 Flesh of the pome with grit-cells, Pyrus (pear). 

 Flesh of the pome without grit-cells, Malus (apples and crab-apples). 

 Ovules many in each carpel, Cydonia (quince). 



MALUS (Apples) 



Stems. — Malus species are either trees or shrubs. In the 

 apple, all rapid-growing shoots develop only leaf buds. 

 Flower buds, which in the apple are "mixed" buds, are al- 

 most always borne on the ends of "spurs" or short twigs. 

 When a "spur" terminates in a flower bud, lateral buds lower 

 down continue the growth of the shoot, hence the crooked 

 appearance of such spurs (Fig. 153). These lateral buds 

 may grow for a year or so, bearing leaf buds at the terminus, 

 and then be stopped in their growth in that direction by the 

 formation of a terminal flower bud. As a rule, a shoot that 

 has once started to bear flowers continues to do so, making 

 but a very short growth of wood each year. Such a shoot is 

 marked by the closely crowded leaf scars, terminal-bud scars, 

 and flower and fruit scars. The position of a fruit is usually 

 marked by a large circular scar surrounded by a number of 

 smaller ones of the same shape. The smaller ones represent 

 scars made by flowers or fruit that failed to develop. It has 

 been recorded generally, particularly for Eastern orchards, 

 that the fruit buds in apples are always terminal, and further- 



