OCR Text |
Show 362 TREES. thus sco the same result fo1lowing from tho effects of climate nnd from an innate spontaneous tcndoncy.1 " 0 • . • • • • In foliage wo ho.vo variegated leaves which arc often mhonted' da~k purple or red loaves, as in tho hazel, barberry, and beech, t_he colom m those two latter trees being sometimes strongly and ~omet~mcs woak~y inherited; 161 deeply-cut leaves; and loaves covered _with pncklcs, ~s m the variety of tho holly well callodferox , wl~c~ is s~Id to reproduce Itse~f by seedY~ In fact, nearly all tho peculiar vanetws ovmcc a 1~;n~on?y,_ moiO or less strongly marked, to reproduce thomselvo~ by seed. . T?Is IS to a certain extent tho case, according to Bosc/"4 with ~hreo vaneti_cs of ~ho olm, namely, tho broad-leafed, lime-loafed, and t~Istcd elm, m whwh latter tho fibres of tho wood arc twisted. Evon with tho hetoropby llous hornbeam ( Ca1pinus betulns), which bears ~n each twig loaves o~ t~:o ~~~~Fos, "several plants raised fr·om seed all rotamcd _th~ s~mo P_eculianty. I will add only one other remarkable case of v~nat1?n 1n ~ohage, nam~ly, tho occurrence of two sub-varieties of the ash w1th slillplo mstoad of pmnatod leaves, and which generally transmit their character by sce~- 156 The o~currenco, in ti·eos belonging to widely different ord~rs, of woopmg and fast1gate varieties, and of trees bearing deeply cut, vancgated, and purple leaves, shows that these deviations of structure must result from some very general physiological laws. Differences in general appearance and foliage, not more strongly ~ar~ccd than tho. o above indicated, have led good observers to ran~ ~s d1stmct species certain forms which arc now known to be_ more vanct1es. Thus a plane-tree long cultivated in England was consJdo~·ed by almost every one as a North American species; but is now ~scm·tamcd bY_ old re~~I·~, as I am informed by Dr. llookcr, to be a vanety. So agam the 'l1!UJC~ pmduln or .filiformis was ranked by such good observers as La~b.crt, Wallich, and others as a true species; but it is now known th~t tho o~1gmal plants, five in number, suddenly appeared in a bed of secdlmgs, rl1lsod at JUr. Loddigo's nursery, from '1'. orientalis; and Dr. llooker has adduced excellent ovic.lonce that at Turin seeds of '1'. pendula have reproduced tho parent-form, '1'. orieutcttis.1"7 Bvcry one must have noticed how certain individual trees regularly ~ut forth and shed their leaves earlier or later than others of tho same specJCs. Thoro is a famous horso-chcsnut in tho Tuilories which is named fr·om 1r,o Gorlron (' Do l'Espcco,' tom. ii. p. 01) describe!:! four varieties of Hobiuin rcmarkaulo from ibeir manner of growlh. m 'Journal of a Horticultural rrour, by CaJcdouirtn Hort. 'oc.,' 1823, p. 107. Alph. Do Candoll c, 'Gcogrnph. llot.,' p. 108::3. Verlot, 'Sur l::t ProclucLion des Varicl6~,' 18y5, p. 55, for tho Barberry. 15 ~ LouJon't> ' Arboretum ct Fruticctum,' vol. ii. p. 508. 153 V or lot,' Des Vari6t6s,' 1865, p. !J2. JH Loudon's 'Arboretum et l<'rutieeium,' vol. iii. p. 137G. m ' Gardener's Chronicle,' 1811, p. G87. lv6 Godron, 'Do l'Espceo,' tom. ii. p. SO. In London't> 'Gardeucr's Mug.,' vol. xii. 1830, p. 371, a vnricgatcd bushy ash is dcscribeJ and figured, as having simple loaves; il originated in Ireland. Jo7 ' G(lruencr's Chron.,' 1801, p. 575. _CHAP. X. TREES. 3G3 leafing so much earlier than tho others. There is also an oak ncar Edinburgh which retains its leaves to a very late period. These differences have been attributed by some authors to the nature of the soil in which tho trees grow; but Archbishop Whately grafted an early thorn on a late one, and vice Vi-"''Sli, and both grafts kept to their proper periods, which differed by about a fortnight, as if they still grow on their own stocks.158 Thoro is a Cornish variety of tho elm which is almost an evergreen, and is so tender that tho shoots are often killed by tho frost; and the varieties of tho Turkish oak ( Q. cerris) may bo arranged as d<Joiduous, sub-evergreen, and ovcrgrccn. 15g Scotch ./J'ir (Pinus sylvestr·is).-I allude to this tree as it bears on tho question of tho greater variability of our hedgerow trees compared with those under strictly natural conditions. A well-informed writer 100 states that tho Scotch fir presents few varieties in its native Scotch forests; but that it " varies much in figure and foliage, and in the size, shape, and colour of its ~'cones, whon·scvcral generations have been produced away from its native "locality." There is little doubt that the highlnnd and lowland varieties differ in the value of their timber, and that they can be propagated truly by seed ; thus justifying Loudon's remark, that "a variety is often of as much ,importance as a species, and sometimes far more so." 101 I may mention one mthor important point in which this tree occasionally varies ; in the classification of tho Coniforre, sections are founded on whether two, three, or five leaves arc included in tho same sheath; tho Scotch fir bas properly only two loaves thus enclosed, but specimens have been observed with groups of three leaves in a shoath.162 Besides these differences in tho semicultivated Scotch fir, thoro are in several parts of Europe natural or geographical races, which have been ranked by some authors as distinct spccies.103 Loudon 164 considers P. pumilio, with its several sub-varieties, as .ftfughus, nuna, &c., which differ much when planted in difiorent soils and only como "tolerably true from seed," as alpine varieties of the Scotch fir; if this wore proved to be the caso1 it would be an interesting fact as showing th11t dwarfing from long exposure to a severe climate is to a certain extent inherited. '.rho l!uwthorn (Orutcegus oxycantlw) has varied much. Besides endless slighter variations in the form of tho leaves and in tho size hardness fleshiness, and shape of tho berries, Londo; 1os enumerates t~enty-nin~ well-marked varieties. Besides those cultivated for their pretty flowers, there arc others with golden-yellow, black, and whitish berries; others 158 Quoted from Royal Irish Academy in 'Gardener's Chron.,' 1811, p. 707. 159 Loudon's 'Arboretum ct Fruticcium :' for Elm, see vol. iii. p. 137G ; for Oak, p. 1840. 100 ' Gardener's Chronicle' 1810, p. 822. ' 101 ' A rborotum et 1!'ruticctum,' vol. iv. p. 2150. 102 'Gardener's Chron.,' 1852, p. G93. 163 See 'Bcitriio-e zur Kcntuil:lS Europiiiscber Pinus-t~·ten von Dr. Cbrisl: :Flora, 1801.' Uo shows illat in tho Obcr-Engadin P. sylvestris nncl montana arc connected by intermediate links. 164 'Arboretum ct Fruticctum,' vol. iv. pp. 2159 and 2189. 165 Ibid., vol. ii. p. 830; Loudon's' Gardcucr'l: l Magazine,' vol. vi. 1830, p. 714. |