214 Miscellaneous. 



lost to their leaves : they devclope themselves fully, although they 

 have no stem to adhere to ; they preserve the spathulate form, but 

 cannot produce the awl- shaped tips of the shoot-leaves. There are, 

 therefore, two forms of leaves on the larch, the one free, the other 

 adherent ; and we have a novel principle very clearly illustrated, 

 that strong axial development (vigour) is a characteristic of adhesion, 

 tvhiJe the reverse (weakness) is characterized by a free system of folia- 

 tion. Any species of Larix will sustain this observation ; and lepto~ 

 lejyis, as a vigorous grower, is the best. 



The characteristics of the foliage described in Larix may be found 

 in a greater or less degree in a great many species of coniferous 

 plants. In Cryptomeria the leaves adhere for four-fifths of their 

 length on vigorous shoots ; but on the more delicate ones they are 

 free for three-fourths or more. In Juniperus the different forms of 

 foliage are well known, especially in J. virginiatia, J. chinensis, and 

 J. communis. On the vigorous shoots adhesion takes place for nearly 

 the full length of the leaves ; but on weaker ones the leaves are very 

 nearly free. In Thuja, Biota, Betinispora, Cupressus, Tliujopsis, 

 indeed most of the section Cupressineoe, these variable degrees of ad- 

 hesion may be found, and always in relation to the absence or pre- 

 sence of vigour : and on this question of vigour it will be well here 

 to make a few remarks. The power to branch I take to be a high 

 mark of vigour. The young seedlings of most coniferous trees grow 

 but a few inches the first year, and have no power to branch ; the 

 power increases with age, and in all cases in proportion to the vigour 

 of the plants. In Thuja, for instance, no branches appear tiU the 

 second year ; they increase in number, until, when in its prime, 

 branches appear from every alternate pair of axils, and, as these are 

 decussate, this gives the fan-like form of growth of which the Arbor 

 vitce affords a familiar illustration. 



This varying power of adhesion in the true leaves, and in con- 

 nexion with vigour, enables us to explain many matters hitherto not 

 understood. For instance, Dr. Lindley describes a form of Biota 

 as B. meldensis, suggesting that from its appearance it must be 

 a hybrid between the red cedar and Chinese Arbor vitce ; it is but 

 B. orientalis with the leaves moderately united. Thuja ericoides 

 of gardens was long supposed to be a Japanese species ; it is but an 

 entirely free-leaved form of Thuja occidentalis. Retinispora ericoides 

 of Zuccarini is but a free-leaved form of some Japanese plant ; and 

 in all probability many species of Retinispora, so marked in herba- 

 riums, are aU forms of one thing with more or less adnate leaves. 

 In all these cases delicacy of growth and freedom of leaves go gra- 

 dually together, as before indicated. 



One of the most remarkable instances of the value of this prin- 

 ciple, however, will, I have no doubt, be in fixing the identity of the 

 Japenese genus Glyptostrobus * of Endlicher with the American 

 Taxodium of Richard. In a shoot one foot in length of the latter 

 we find perhaps four or six branchlets ; in the same space in Glyp- 



* Note by the proof-reader. — It was the intention of the avithor to refer his re- 

 marks on Glyptostrobus to G. sinensis, Endl. 



