164 The Trees of Great Britain and Ireland 



Aria. In winter, specimens of cultivated Sorbus fennica show the following 

 characters represented in Plate 45 : 



Twigs : long shoots glabrous, shining, dark brown, with a few scattered lenticels. 

 Leaf-scar crescentic, very narrow, set obliquely on a reddish brown, slightly projecting 

 cushion ; it shows a varying number of bundle traces,^ 3, 4, or 5, and may thus be 

 distinguished from other species of Sorbus, as Pyrus Aucuparia has 5 dots on the scar, 

 while Pyrus Aria, intermedia, and latifolia have only 3. Terminal bud large, conic, 

 tomentose, especially at the apex. Lateral buds small, either appressed to the stem 

 or diverging from it at an acute angle. Bud-scales few, densely pubescent on the 

 outer surface, and ciliate in margin. Short shoots ringed, pubescent, bearing a 

 terminal bud.^ 



Distribution 



The ioxm fennica occurs plentifully in Scandinavia, where it grows wild, repro- 

 ducing itself naturally by seed, and behaving as a true species. It extends in Norway, 

 according to Schiibeler, up to lat. 66 14' on the west coast as a wild plant, and in 

 Sweden up to 60 wild and 62" planted ; it also occurs in Finland, but is not recorded 

 from other parts of Russian territory. In Central Europe it only occurs sporadically, 

 and apparently always in company with the parent species ; it is recorded from 

 various mountain stations in France, Switzerland, Germany, and Austria. 



The hybrids which occur in the Isle of Arran have attracted much attention and 

 discussion. Formerly it was believed that Pyrus Aucuparia, Pyrus intermedia (var. 

 scandica), and Pyrus fennica, all occurred in a wild state. Koehne,^ however, con- 

 siders that (excepting Aucuparia) all the plants in question on the island are hybrids, 

 there being two sets, one typical fennica, while the other set comprises forms between 

 that and scandica. This view, which excludes one of the parents (viz. scandica), 

 implies that these hybrids, once established, may under favourable conditions reproduce 

 themselves naturally and behave generally as true species. 



N. E. Brown says of this species that it is " rare and perhaps not indigenous 

 except in Scotland " ; but he has seen specimens from Kent, Sussex, Hants, Somerset, 

 Gloucester, Leicester, Stafford, Cumberland, Roxburgh, Arran, and Dumbarton. 

 He thinks that Arran seems to be the only truly native locality for this tree in the 

 British Isles, and believes that the Arran plant placed under intermedia is a form of 

 it. Watson, however, states in his Compendium, p. 510, that Borrer held it to be 

 wild in North Hants between Farnham and Farnborough, where it was observed 

 sparingly along with Aria and Aucuparia, both more plentifully. A specimen picked 

 by James M'Nab in Darenth Wood, Kent, is, according to Watson, identical with 

 Arran specimens. 



There is a fine tree on the edge of a shrubbery close to Wilton House, 

 Wilts, the seat of the Earl of Pembroke, about 50 feet by 5. 



' If the dots are not plainly visible externally, they can be seen clearly on paring off the epidermis of the scar. 



' The twigs in winter described above clearly show the hybrid origin of this species ; the varying number of dots on the 

 scar, the pubescence and shape of the scales, etc. show the influence of Pyrus Aucuparia. 



' Koehne, y<JKr. of Hot. 1897, p. 99. See also Kcv. Dr. Landsborough's account of the Arran hybrids in Tram. Bot. 

 Soc. Edin. xxi. $6 (1S97). 



