Page:Natural History Review (1862).djvu/31

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20
ORGINAL ARTICLES.

no respect from a vigorous annual leaf-branch. It bears linear leaves, of the usual form, each of which has a leaf-bud in its axil. These leaf-buds are subglobose or ovate, and are covered by brown scales (nieder blätter). The two lowest of these scales, which are the most important as respects the true morphological structure of the cone-scale, stand right and left, as in most plants. These are the leaves commonly called the cotyledons of the branches. In these elongated cones there is generally no passage from the woody (seed-bearing) scales of the cone to the leaf-buds. Although I have examined more than 100 such scales, I have met with but few intermediate states explanatory of the true nature of the woody scales. In such intermediate states the cone is not, as usual, shortly ovate, but oblong, and attenuated at the tip, and the woody scales are a little emarginate at the apex. In the scales which appear to pass into the leaf-buds this emargination becomes by degrees more and more deep, till at last, near the summit of the cone, where they are more laxly imbricated, the woody scales are divided, almost to the base, into two obovate or ovate lobes, which are rounded at the apex, or a little mucronate, and are made inæquilateral, by an indentation on the outer side, below the apex. Each of these lobes bears on its inner and upper side, towards the lower margin, the ovate-globose rudiment of an abortive bud. Between the main axis and the bipartite scale I could see no bud. Further up on the axis the intermediate forms are further advanced. The scale is completely bipartite, and the segments are smaller, oblong, subtrapezoidal, obliquely truncate above, with rounded angles, and often wider upwards. As these scales present not even a trace of an ovule, they can no longer, with propriety, be called carpels; but it is most important to observe, that, between their segments and the axis, a leaf-bearing bud, covered with scale-like leaves, is developed. Still higher up on the axis the segments of the woody scale are smaller and more distant from, one another, occupying, by degrees, a more and more lateral position with respect to the leafy bud developed between them and the axis, and approach gradually more and more in size, position, and shape to the two lateral scales of an ordinary leaf-bud, so as at last to pass completely into it.

It is thus clearly proved that the woody scale of the larch cone consists of the first two lateral scales (squamiform leaves) of an undeveloped leaf-bud placed in the axil of the bract which supports the woody scale, these two lateral scales springing in a united state from the outer side of the axis and ascending obliquely. This structure of the woody scale of the larch cone, and consequently of all Abietineæ, is so clearly and irrefutably shown by these monsters, that all other opinions on the morphology of the scales of Conifers are thereby demonstrated to be erroneous.


    Seringe. Eléments de botanique, 1841, t. xiii. f. 12; et Decandolle, Organographie végétale, 1828, tab. 36, f. 3.