"Another example of retrieving lost leaders may be quoted as illustrative of many in similar circumstances. _Pícea Webbiana_ had its leader completely destroyed down to the first tier of laterals. There was no such provision left for inducing leaf-buds as was the case with _P. Lowii_ above referred to. Resort must, therefore, be had to one of the best favoured laterals, but how is it to be coaxed from the horizontal position of a lateral to the perpendicular position of a leader? The uninitiated in these matters, and, in fact, practical gardeners generally, would at once reply, by supporting to a stake with the all-powerful Cuba or bast-matting. But no. A far simpler method than that, namely, by fore-shortening all the laterals of the upper tier but the one selected for a leader. Nature becomes the handmaid of art here; for without the slightest prop the lateral gradually raises itself erect, and takes the place of the lost leader. All that the operator requires to attend to is the amputation of the laterals until this adventitious fellow has gained a supremacy. Singular provision in nature this, which, thanks to the undivided attention of a careful observer, has been fully appreciated and utilized."
[211] 'Variation of Animals and Plants,' ii, p. 277.
[212] Quoted in 'Gard. Chron.,' 1867, p. 654.
[215] Planchon and Marès, 'Ann. Sc. Nat.,' 5 ser., tom. vi, 1866, p. 228, tab. xii.
[216] 'Bull. Acad. Belg.,' xviii, part ii, p. 293.
DEVIATIONS FROM THE ORDINARY FORM OF ORGANS.
In a morphological point of view the form of the various parts or organs of plants and the changes to which they are subjected during their development are only second in importance to the diversities of arrangement and, indeed, in some cases, do not in any degree hold a second place.
Taken together, the arrangement, form, and number of the several parts of the flower, make up what has been termed the symmetry of the flower.[217] Referring to the assumed standard of comparison, see p. 4, it will be seen that in the typically regular flower all the various organs are supposed to be regular in their dimensions and form. At one time it was even supposed that all flowers, no matter how irregular they subsequently became, began by being strictly symmetrical or regular, and that subsequent alterations were produced by inequality of growth or development. The researches of organogenists have, however, dispelled this idea of unvarying primordial regularity, by showing that in many cases flowers are irregular from the very first, that some begin by being irregular, and subsequently become regular, and even in some cases resume their original condition during the course of their development.[218] Under these circumstances an artificial standard of comparison becomes almost an absolute necessity for the time being.