







ANATOMY, AND LIFE-HISTORY OF THE CONIFEUjE. 



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as foliar, by others as axial. Thus Tristan considered the 

 needles " as abortive branches, a view at one time adopted by 



Meel 



lan, but since renounced in favour of the view that the 



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fascicle consists of true leaves emerging from the side of an 

 arrested shoot bearing a " dormant bud at the apex " *. 



The fascicles of leaves originate within the axil of a bud-scale 

 or of a protomorphic leaf. This position then indicates their 

 bud-like character. If examined in a very early stage of growth, 

 they will be seen to consist of an axis whose growth in length is 

 arrested but which produces at the base two lateral and five, 

 six, or more sheathing- scales of perular nature surrounding a 

 number of tubercles (2-5), which it is easy to trace in different 

 buds from the initial stage to that of the perfectly developed 

 needle or leaf. The perulse are arranged in spirals, while the 

 needles are verticillate. The number of leaves in a verticil 

 varies from 2 to 5, rarely one only is produced, but this solitary 

 condition is rather apparent than real t. The form of the leaves 

 varies according to the number in each verticil, being plano- 

 convex where there are two only, triangular in other cases. 



In tracing the development of the several fascicles of leaves 

 along the whole length of a young shoot, although of course the 

 youngest are nearest the apex, yet it is remarkable how nearly 

 or the same size and stage of development are all the fascicles. 



Occasionally it happens that the growing point at the apex of 

 the contracted branch, instead of remaining dormant, is prolonged 

 into a shoot with primary leaves and leaf-buds, see fig. 9. 



The anatomical structure of the needles of Pinus varies 

 slightly in the different species, and has, as also that of the 

 primordial leaves, been already alluded to in a former page. It 

 may suffice here to say that in all essentials the structure is that 

 of the leaves with the xylem part of the bundle directed upwards 

 and inwards. 



The evidence derived from comparative morphology, including 

 teratology, development, and minute anatomy, is entirely in favour 



Tristan, I c. p. 246 ; Meehan, on the Leaves of Conifers, Proc. Atner. 



Assoc. Adv. Science (1808), B, p. 1, also in Proc. Acad. Nat. Sc. Philadelphia, 



May 14 (1868), p. 122, Journal of Botany vol. viii. (1870), p. 133, and 



Bulletin of Torrey Botanical Club, August 1885, vol. xii. p. 82. 



t Kronfeld, " Bemerkungen iiber Coniferen," quoted in Botan. Centralblatt, 



n * 3 » 1889 » p. 66, cites instances of variations in the number of leaves in the 

 fascicles of Pinus. 















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