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DB. M. T. MASTERS Off THE MORPHOLOGY, 



Mirbel, speaking of the buds of Finns, says :— " Ces bourgeons 

 naissent dans l'aiselle des veritables f euilles, lesquelles sont seches 







minces et fugaces dans les arbres qui ont atteint leur troisieme 

 ou quatrieme annee, mais sont vertes et herbacees dans ceux qui 

 n'ont qu'un ou deux ans . . . les veritables feuilles . . . dans l'aiselle 



desquelles naissent les bourgeons 



acquierent quelquefois 



sur les branches des vieux pins la forme et la consistance qu'elles 

 offrent toujours sur les jeunes tiges ; et c'est ainsi que les especes 

 du genre reprennent, comme par accident, les caracteres qui 

 semblent etre les plus conformes a leur organisation primitive." 



Eichard also, in his " Memoire sur les Conif eres," says, " Les 

 feuilles sont d'abord solitaires dans les Pins, pendant la premiere 

 et la seconde annee apres leur germination," alluding, of course, 

 to the primordial leaves *. 



A similar formation of leaves homologous with the primordial 

 leaves is seen, in some cases, on the branches or stalks immediately 









supporting the cones, as in Pinus excelsa &c. 



The structure of the primordial leaves of Pinus, although essen- 

 tially the same as that of the secondary leaves to be hereafter noted, 

 yet presents some interesting features. The epidermis is papular 

 and there is no hypoderm. The mesophyllis made up of spheroid 

 cells, the walls of which are not infolded like those of the second- 













ary leaves. The endoderm and enclosed pericycle are not well 

 marked off, but the central fibro-vascular bundle is perfectly con- 

 formed and has the same essential structure as in the secondary 

 leaves, with this important exception that, whereas in the 

 secondary leaves the bundle generally divides into two, in the 

 primordial leaves it remains undivided. The resin-canals, when 

 present, are sometimes placed in a different position to that which 

 they occupy in the secondary leaves ; thus, in Pinus Lambertiana 

 the resin-canals of the primordial leaves are close to the lower 

 epidermis, while in the more permanent leaves they are in the 

 centre of the mesophyll. The mechanical structure as above in- 

 dicated is less highly developed than in the secondary leaves, 

 which have to bear a greater strain. 





* Mirbel/* Observ. sur la famille des Vegetaux, Coniferes/* in Ann. du Museum 

 d'Hist. Nat. xv. 1810, p. 475. 



Henry, " Beitr. z. Kenntniss d. Laubknospen," in Act. Acad. Leopold.-Cur. xix. 

 P. i. p. 93, tab. xii. fig. 6 (1837). 



M. Kronfeld, * Ueber Polyphyllie b. Pinus Mughus u. silvestris? in Verhandl. 

 d. k. k. zool.-bot. Gesellscb. in Wien, 88, Bd. iv. 1888. (Not seen.) 







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