1078 The Trees of Great Britain and Ireland 



amidst the chaparral, and where I saw it on the boundary between Oregon and 

 California, never attained a greater height than 30 ft. with a maximum diameter of a 

 foot, all the trees being narrowly pyramidal with short branches, and bearing 

 numerous whorls of unopened cones on the main stem. Its range here appears to 

 be between 2500 and 3000 ft. Sargent says it occasionally attains a height of 100 

 ft., but neither Mr. F. R. S. Balfour nor myself saw any but small trees, those of 

 exceptional size being probably restricted to deep ravines on good soil. The hills 

 on which it grows are very liable to be swept by forest fires, and there is no doubt 

 that it rarely if ever reproduces itself, except on burnt areas, ^ when the scorched 

 cones let out the seeds. It is often attacked by mistletoe. In the same region it is 

 occasionally accompanied by a peculiar variety of P. contorta with small cones, a tree 

 of similar size and habit. 



P. tuberculata was discovered by Hartweg^ in 1847 in the Santa Cruz 

 mountains, about twenty miles north of Monterey, and was introduced by him into 

 the garden of the Horticultural Society, London, in the same year. This species 

 grows slowly in England, and is of rare occurrence in collections ; the best specimen 

 we have seen is a tree 50 ft. high at Bury Hill, Dorking, which divides into several 

 stems at i ft. from the ground, where it girths 10 ft. 5 in. There is an ill-shaped 

 and decaying tree at Bayfordbury, 36 ft. high, dividing at 3 ft. from the ground 

 into two stems, 3 ft. and 3^ ft. respectively in girth. A branch of the tree 4 ft. in 

 length bore forty-one cones. A tree at The Heath, Leighton Buzzard, measured by 

 A. B. Jackson in 1908, was about 35 ft. high. Smaller specimens occur at Kew, 

 Blackmoor in Hants, and Ochtertyre. 



In New Zealand,^ this species is a rapid grower, second only to P. radiata. At 

 Canterbury, three varieties have arisen, all of which come true from seed and are 

 very constant in character. (A. H.) 



^ A graphic account of this pine and its relation to forest fires, by Muir in Harper's Magazine, xxii. 715, is reproduced 

 in Card. Chron. xxiv. 786 (1885). Jepson, in Flora W. Mid. California, 23 (1901), says that a burnt forest of the knob-cone 

 pine is promptly re-sown with its own seed. 



2 Hartweg described it in Joum. Hort. Soc. ii. 189 (1847), but erroneously supposed it to be identical with P. 

 californiana, Loiseleur. 



3 Adams, Genus Finns, 6, paper read at the Philosophical Institute, Canterbury, New Zealand, 7th August 1907. 



