Chap. X. TKEES. 387 



by seed ; thus justifying Loudon's remark, that " a variety is often 

 " of as much importance as a species, and sometimes far more so." 161 

 I may mention one rather important point in which this tree occa- 

 sionally varies; in the classification of the Coniferse, sections are 

 founded on whether two, three, or five leaves are included in the 

 same sheath; the Scotch fir has properly only two leaves thus 

 enclosed, but specimens have been observed with groups of three 

 leaves in a sheath. 192 Besides these differences in the semi-culti- 

 vated Scotch fir, there are in several parts of Europe natural or 

 geographical races, which have been ranked by some authors as 

 distinct species. 103 Loudon 164 considers P. pumilio, with its several 

 sub-varieties, as mughus, nana, &c.,which differ much when planted 

 in different soils, and only come "tolerably true from seed," as 

 alpine varieties of the Scotch fir ; if this were proved to be the case, 

 it would be an interesting fact as showing that dwarfing from long 

 exposure to a severe climate is to a certain extent inherited. 



The Hawthorn (Crataegus oxyacantha) has varied much. Besides 

 endless slighter variations in the form of the leaves, and in the size, 

 hardness, fleshiness, and shape of the berries, Loudon 165 enumerates 

 twenty-nine well-marked varieties. Besides those cultivated for 

 their pretty flowers, there are others with golden-yellow, black, and 

 whitish berries; others with woolly berries, and others with re- 

 curved thorns. Loudon truly remarks that the chief reason why 

 the hawthorn has yielded more varieties than most other trees, 

 is that nurserymen select any remarkable variety out of the 

 immense beds of seedlings which are annually raised for making 

 hedges. 1 he flowers of the hawthorn usually include from one to 

 three pistils; but in two varieties, named monogyna and sibirica, 

 there is only a single pistil ; and d'Asso states that the common 

 thorn in Spain is constantly in this state. 166 There is also a variety 

 which is apetalous, or has its petals reduced to mere rudiments. 

 The famous Glastonbury thorn flowers and leafs towards the end of 

 December, at which time it bears berries produced from an earlier 

 crop of flowers. 167 It is worth notice that several varieties of the 

 hawthorn, as well as of the lime and juniper, are very distinct in 

 their foliage and habit whilst young, but in the course of thirty or 

 forty years become extremely like each other ; 168 thus reminding us 

 of the well-known fact that the deodar, the cedar of Lebanon, and 



lei 'Arboretum et Fruticetum,' 164 'Arboretum et Fruticetum,' vol. 



vol. iv. p. 2150. iv. pp. 2159 and 2189. 



ly2 'Gardener's Chron.,' 1852, p. 165 Ibid.,' vol. ii. p. 830; Loudon's 



093. ' Gardener's Mag.,' vol. vi. 183u, p. 



163 See ' Beitr'age zur Kenntniss 714. 



Europaischer Pinus-arten von Dr. 166 Loudon's 'Arboretum et Fru- 



Christ : Flora, 1864-.' He sbows that ticetum,' vol. ii. p. 834. 



in the Ober-Engadin P. sylvestris and 16: Loudon's ' Gardiner's Mag.,' vol. 



montana are connected by interme- ix. 1833, p. 123. 



diate links. 168 Ibid., vol. xi. 1835. p. 503. 



