









310 



DR. M. T. MASTERS ON THE MORPHOLOGY, 





two larain© (bract and seed-scale). The course of development 

 in Pinus Strobus is the same. Baillon* gives a similar account 

 of the development in Pinus recurva, as does Oersted t of 

 that of P. pumilio ; but what he speaks of as the median lobe 

 of the axillary scale, and which, he says, is developed subse- 

 quently to the other part of the scale, appears to be the true 

 apex of the scale, which is terminated by a mucro and dilates 

 laterally into the umbo. The thickened end or apophysis of the 

 cone-scales is peculiar to some sections of the genus Pinus and 

 is an after-development. At first, as in P. Zaricio, the scale is 

 nearly flat, as it remains in P. Strobus, P. Cembra, &c. ; but as 

 growth goes on, the activity of growth is most manifested on the 

 under or outer surface, so that the scale becomes unsymmetrical 

 and thicker below the (originally) central umbo than above it. 

 In Pinus Coulteri the scales retain their primitive equality of 

 proportion, and terminate in a central pyramidal point. 



Andrew Murray regarded this umbo and mucro as the repre- 

 sentative of a petal ! The same author also suggested, as an 

 alternative hypothesis, that the bract was the homologue of the 

 petal, the fruit-scale of the disc ; while the wing and test of the 

 ovule or seed were regarded by him as pericarp +• 



Anatomical Structure. — The anatomy of the bract and seed- 

 scale in the Abietinese is essentially the same as in the other sub- 

 orders, the vascular cords of the bract having always the phloem 

 below, the xylem above ; while in the fruit-scale the relative posi- 

 tion is reversed, but occasionally, as in Pseudolarix Kaempferi, 

 the bracts retain for a longer or shorter period a purely cellular 

 condition, in which no differentiation into xvlem and phloem is 

 observable. In this plant the bract and the fruit-scale have a 

 common cellular basis, and the vascular cords pass direct from 

 the axis into the fruit-scale, leaving the bract, at any rate at first, 

 wholly cellular. The essential structure of the fruit-scale, as in 

 all other Conifers, is the same as in the needles of Sciadopitys or 

 the cladodes of Ruscus. In the bract there is generally a single 

 fibro-vascular bundle, whilst in the fruit-scale there are several 

 in one plane. 



The central axis or core of the cone to which the fruit-scales 































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* Baillon, Recherches Organogeniques, 1860, t. 1 

 t Oersted, Bidrag til jNaaletrternes Morphologi ( 



\ A. Murray in Gard. Chron. (1866), pp. 8, 852. 



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