Pinus 1 1 09 



PINUS BANKSIANA, Jack Pine^ 



Pinus Banksiana^ Lambert, Genus Pinus, i. t. 3 (1803); Loudon, Arb. et Frut. Brit. iv. 2190 

 (1838); Kent, Veitch's Man. ConifercB, 315 (1900); Mayr, Fremdldnd. Wald- u. Parkbdume, 

 353 (1906); Sargent, in Bot. Gazette, xliv. 226 (1906) j Clinton-Baker, Illust. Conif. i. 9 

 (1909). 



Pinus sylvestris, Linnaeus, var. divaricata, Aiton, Hort. Kew. iii. 366 (1789). 



Pinus divaricata, Dumont de Courset, Bot. Cult. iii. 760 (1802); Sargent, Silva N. America, xi. 147 



t. 588 (1897), and Trees N. America, 27 (1905); Masters, m Journ. Linn. Soc. {Bot.) xxxv. 



620 (1904). 

 Pinus rupestris, Michaux f., Hist. Arb. Amer. Sept. i. 49, t. 2 (i8io). 

 Pinus Hudsoni, Poiret, in Lamarck, Encycl, v. 339 (1804). 

 Pinus Hudsonica, Parlatore, in DC. Prod. xvi. 2, p. 380 (1868). 



A tree, attaining in America in favourable situations, 90 ft. in height ^ and 6 ft. 

 in girth ; but usually smaller, and sometimes becoming a mere shrub. Bark thin, 

 dark brown, irregularly divided into narrow connected scaly ridges. Young 

 branchlets slender, flexible, glabrous, greenish, turning purplish brown in the first 

 winter and following year. Buds ovoid, pointed, covered with resin, about \ in. 

 long. 



Leaves in pairs, the clusters not very dense on the branchlets, persistent for two 

 or three years, spreading, \ to \\ in. long, more or less curved, slightly twisted, 

 serrulate, ending in a short cartilaginous point, with about ten stomatic lines on each 

 surface ; resin-canals median ; basal sheath -^ to -^ in. long, lacerated. 



Cones lateral, solitary or clustered, shortly stalked, directed towards the apex 

 of the branchlet, much incurved, oblique at the base with the scales on the outer 

 side most developed, ovoid-conic, i^ to 2 in. long, yellow and shining when ripe, 

 often remaining unopened for several years ; scales thin and stiff, about f in. long 

 and :|- to f in. broad ; apophysis raised, pyramidal ; umbo depressed or projecting, the 

 minute incurved prickles of the first year usually becoming obsolete. Seeds only 

 developed on the large scales of the outer side of the cone, triangular, blackish, \ in. 

 long ; wing \ in. long, broadest at the middle, full and rounded at the apex. 



This species is readily distinguished by the short needles, and the occurrence of 

 a whorl of buds, branchlets, or cones in the middle of each year's shoot when this is 

 well-developed. The cones are peculiar in colour, shape, and direction. 



This species has the most northerly range of all the pines of eastern North 

 America, extending in Canada over a vast territory, bounded on the north by 

 a line drawn in a north-westerly direction from northern Nova Scotia, lat. 45°, to near 

 the southern end of Great Bear Lake, lat. 65°, not touching Hudson Bay or James 



1 The tree is commonly known by this name in Michigan, Minnesota, and Canada. Scrub pine, Grey pine, and Black 

 pine are also used in New England and Canada. From Quebec to Hudson Bay it is called Cypress. Banksian pine is often 

 used in books on forestry. 



2 This is the correct name, according to the rules for botanical nomenclature adopted by the Vienna Congress. Cf. 

 Graebner in Mitt. deut. dend. Ges., 1908, p. 68, who points out that the name divaricata was not accompanied by a sufficient 

 description. Sargent now accepts P. Banksiana as the correct name. 



' This is the maximum size given in U.S. Forest Service Circ. 57 (1907). According to Mayr, op. cit. 356, Macoun 

 gives IIS ft. (35 metres) as the height which the tree sometimes attains in Canada. I have seen no exact measurements 

 quoted, higher than those taken by me in Minnesota. 



