PYRUS 271 



III. AUCUPARIA. MOUNTAIN ASH, SERVICE. 



Trees with pinnate leaves. Fruit except in P. Sorbus resembling that 

 of Aria : americana, Aucuparia, sambucifolia, scopuiina, Matsumurana, 

 Sorbus, thianshanica, Vilmorinii. This well-marked group includes some 

 of the handsomest species, especially in regard to fruit and foliage. Many 

 are of elegant habit. They are propagated by seed, or by grafting on 

 seedlings of their own group. The Service tree (P. Sorbus) is distinct 

 because of its fewer, large, dull-coloured, and normally pear-shaped fruits, 

 as compared with the small brightly coloured round fruits of the mountain 

 ashes. P. spuria is a hybrid with the Aronia group. (See also note 

 under preceding section as to hybrids with Aria.) 



IV. ARONIA OR ADENORACHIS. CHOKEBERRIES. 



Two North American shrubs with simple leaves bearing glands on 

 the upper surface of the midrib. Fruits small, red or black : arbutifolia, 

 melanocarpa. These are handsome, deciduous shrubs forming a dense 

 thicket of stems ; propagated by division, by cuttings, or by seeds. 



V. MALUS. CRABS. 



Trees and shrubs with simple, sometimes deeply lobed leaves; 

 rounded or somewhat cone-shaped fruits, with usually a cavity where the 

 stalk is inserted. Styles joined at the base: angustifolia, baccata, 

 coronaria, crat&gifolia, floribunda, Halliana, ioensis, Malus^ Nied- 

 wetzkyana, prunifolia^ Ringo, rivularis, Sargentii, Scheideckeri, sikki- 

 menst's, spectabilis, Toringo, and Zumi. 



As ornamental trees, and especially in regard to flower, the crabs rank 

 first among all the groups of Pyrus. In all the range of flowering trees 

 and shrubs there is nothing more beautiful and effective than the best 

 of this group, such as P. floribunda, Scheideckeri, spectabilis, etc. In 

 regard to fruit also it includes some particularly valuable species, such 

 as P. baccata, P. prunifolia, P. Ringo, etc. The Malus group is 

 peculiarly liable to attacks of the white woolly aphis, known as American 

 blight, and scale insects. A winter dressing of the caustic soda wash 

 should be applied, and in summer a spraying with an emulsion of 

 paraffin and soap. So far as I am aware, there is no hybrid between 

 this group and any other of the sections of Pyrus, and the fact that it 

 will not intergraft with them seems to show that a greater gap separates 

 it from them than the older botanists imagined, and that there is good 

 ground for treating it as a distinct genus. The various members have 

 hybridised with each other very freely, so that with many one cannot rely 

 on seeds reproducing the parent exactly. The following species, for 

 instance, are all linked together by a series of hybrids: Malus, baccata, 

 prunifolia, Ringo, and Toringo. Some, probably faost of them, can be 

 rooted from cuttings made of leafless shoots in early winter, and put in 



