214 Miscellaneous. 



lost to their leaves : they develope 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 cliaracteristic of adhesion, 

 while the reverse (weakness) is characterized hy a free system of folia- 

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

 lejiis, 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. virginiana, J. chinensis, and 

 t/". 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, Retinispora, Cupressus, Thnjopsis, 

 indeed most of the section Cupressinea;, 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 till 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 JBiota 

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

 a hybrid betiveen 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 all forms of one thing witli 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 

 Jfipenese genus Glyptostrohus * of Eudlicher with the American 

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

 wo find perhaps four or six branchlets ; in the same space in (ilyp- 



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

 marks on (ilt/plostrobus to G. sincnuis, Endl. 



