Pyrus 163 



PYRUS PINNATIFIDA, Bastard Mountain Ash 



Pyrus pinnatifida, Ehrhart, "Plantag." 22, ex Beitrdge zur Naturkunde, vi. 93 (1791); Loudon, 

 Arb. et Frut. Brit. ii. 915 (1838) ; N. E. Brown, in Eng. Bot. iii. ed. Suppl. 168 (1892) ; Gard. 

 jChron. xx. 493, fig. 78 (1883). 



Pyrus semipinnata. Roth, En, PI. Phcen. in Germ. i. sect. post. 438 (1827). 



Pyrus fennica, Babington, Man. Eng. Bot. ed. 3, p. in (185 i). 



Sorbus hybrida, Linnaeus, Sp. PI. 684 (1762); Schiibeler, Viridarium norvegicum, ii. p. 476. 



Sorbus fennica. Fries, Sumtna Veg. Scand. 42 (1846). 



A species of hybrid origin, occurring as a small tree, which may attain 50 feet 

 in height, with smooth, grey bark. Leaves variable in shape, mostly pinnate or 

 deeply cut at the base, with 1-4 pairs of segments more or less separate; the upper 

 part cut into deep sharp-toothed lobes; green and glabrous above, grey tomentose 

 below. Flowers white in loose corymbs ; styles 3, woolly at the base ; fruit small, 

 globular, coral red, and resembling that of Pyrus Atuuparia. 



Varieties 



This form, the parents of which are P. Aucuparia and P. intermedia, must be 

 carefully distinguished (see p. 143) from Pyrus hybrida, Moench, a shrub of different 

 origin. 



Pyrus Thuringiaca, Ilse,^ a cross between P. Aucuparia and P. Aria, is 

 generally included under P. pinnatifida, from which it differs only in the leaf, 

 whiter beneath, having its upper part lobulate or dentate and not deeply lobed. 



Sorbus arranensis, Hedlund,^ is the name given to a form occurring in the Isle 

 of Arran, which is intermediate between P. pinnatifida and P. intermedia, and closely 

 resembles the latter, differing only in the deeper and more irregular lobing of the 

 leaf 



The hybrid forms, which are intermediate between P. pinnatifida and P. 

 Auctiparia, are generally regarded as varieties (van satureifolia ^ and var. decurrens *) 

 of the latter species, and will be mentioned in our account of the mountain ash. ' 



Identification 



Pyrus pinnatifida and the intermediate hybrids are variable and inconstant in 

 the shape of the leaf There is no difficulty, however, in their identification, if it be 

 noted that hybridity may be suspected in all cases where the leaves vary on the 

 one hand from the regularly pinnate separate leaflets of Pyrus Aucuparia, and on 

 the other from the regular uniform lobing or serration of Pyrus intermedia or Pyrus 



' In/ahresb. Bot. Gart. u. Mus. Berlin, i. 232 (1881). 

 * In Kon. Sv. Veten. Akad. Handl. 1 90 1-2, p. 60. 

 Koch, Dendrologie, i. 189 (1869). 

 Koehne, Deutsche Dendrolegie, 248 (1893). This variety is commonly known as Pyrus lanuginosa, Hort. 



