Pinus io 75 



measured here being 120 ft. high by 13^ ft. in girth. It extends southwards to the 

 San Bernardino and the San Jacinto ranges, up to 8000 ft. elevation, in the 

 Cuyamaca mountains, and finds its most southerly point ' on the San Pedro Martir 

 mountain, 2 in Lower California. 



P. ponderosa was first mentioned by Lewis and Clarke, who saw it in 1804 on 

 the Upper Missouri, on their memorable journey across the Rocky Mountains. It 

 was not made known to science, however, until David Douglas found it 8 on the 

 Spokane river, in Washington, in 1826, and in the Companion to the Botanical 

 Magazine, ii. in, published in 1836, mentioned it as a new pine under the name 

 of P. ponderosa. This name was taken up in 1836 by Lawson, 4 to whom Sargent 

 attributes its description, which was taken from a tree in the Caledonian Horti- 

 cultural Society's Garden, raised from the seeds sent by Douglas in 1827 to the 

 London Horticultural Society. 



The variety Jeffreyi was discovered by Jeffrey in October 1852 in the Shasta 

 valley, in northern California, and introduced in the following year. 5 



Cultivation 



So far as I have seen, this tree succeeds best and attains the greatest size on 

 dry, well drained, but deep soil in the south of England, while it often becomes 

 unhealthy and dies in damp situations ; and, though perfectly hardy 6 in Scotland, 

 is not so large or so thriving there as in the south. It ripens seeds freely in 

 good seasons, from which many plants have been raised at Tortworth and 

 other places. The seedlings are best raised in a box and planted out when a year 

 or two old ; when once established they grow fast, and do not seem to suffer from 

 early or late frosts. 



There are several trees of P. ponderosa in England, which are about 90 ft. in 

 height and some over ; but we have seen none to equal the tree at Powis Castle 

 near the Welshpool entrance to the park, which, when I measured it in 1908, was 

 105 ft. high 7 and 10 ft. in girth with a clean bole of about 60 ft. 



At Bayfordbury a tree planted in 1837, an d growing on good loamy soil, was 

 carefully measured with a sextant and different base lines in 1906, when it was 

 100^ ft. in height, its girth being 9 ft. 4 in. Exactly three years later, in April 



1 The southern form, growing on the mountains east of the San Rafael valley of southern California, and on the moun- 

 tain of San Pedro Martir, in a dry climate, is figured in Garden and Forest, v. 184, fig. 28 (1892), under the name P. Jeffreyi, 

 var peninsularis, Lemmon, in yd Report Calif. State Forestry Board, p. 200 (1891). 



1 Brandegee, in Zoe, iv. 201 (1893), describes this mountain as a plateau 7000 to 8000 ft. elevation, with ridges 2000 

 to 3000 ft. higher. It is cold in winter, ice lasting until May, and the rainfall is considerable. P. Jeffreyi is the most common 

 tree on the plateau, a few trees of P. Lambertiana occurring on the ridges. P. Parryana is common at lower elevations than 

 the plateau. 



3 A specimen, collected by Douglas, in the Kew Herbarium, bears a parasitic plant, Arceuthobium occidentale, Engelm., 

 figured by Loudon, t. 2137, as A. oxycedri, Bieb. 



1 Lawson, Agricultural Manual, 354 (1836). 



5 These particulars are taken from Jeffrey's advice note, which Prof. I. B. Balfour has allowed us to consult. 



At Thorpe Perrow, Bedale, all the conifers raised from seeds collected by Hartweg were killed in the severe winter of 

 1860-61, when 46 of frost were registered, except P. Benthamiana, the Californian coast variety of P. ponderosa, of which two 

 fine trees were surviving in 1888. Cf. Gard. Chron. iii. 236 (1888). 



7 This is the tree mentioned in the notes supplied to the Royal English Arboricultural Society on their visit in 1909 as a 

 Corsican pine, No. 6. 



