This section is from the book "The Gardener's Monthly And Horticulturist V26", by Thomas Meehan. See also: Four-Season Harvest: Organic Vegetables from Your Home Garden All Year Long.
At the meeting of the Botanical Section of the Academy of Natural Sciences of Philadelphia, on the 12th of May, Mr. Thomas Meehan called attention to a paper contributed by him to the " Proceedings of the American Association for the advancement of Science,"p. 277, vol. xix, 1870, in which, contrary to the accepted hypothesis that a fasciated branch was due to "over luxurance" or a high condition of vitality, he showed that the result was due to a degradation of vital power. A number of phenomena conceded to result from low vital conditions were shown to be inseparably connected with fasciation, the essential feature of which is the production of an extraordinary number of buds with a corresponding suppression of the normal internodal spaces.
This is precisely the condition of a flowering branch, and all its attendant phenomena find their analogue in a fasciated stem. Taking a composite flower in illustration - a sunflower for instance - we find on the receptacle a coil of many hundred florets, each with a chaffy scale at the base. Each of these florets in morphology represents a branch, and the scale a leaf or bract from the axil of which the branch would have sprung. If we imagine the head uncoiled, and every thing in a normal vegetative condition or distinct from the condition of inflorescence, we might have a sunflower plant a hundred feet high or more. But with the approach to the flowering stage we have a suppression of vegetative development, with a highly accelerated development of buds out of which are morphologised the floral parts.
The receptacle on which the involucral scales and other parts of inflorescence in a compound flower, had also its analogue in the thickened stems which bore the buds in a fasciated branch.
The phenomena which indicated low vital power in the fasciated branch, were all manifested in a flower. Taking the test of vital power as the ability to retain life under equal circumstances.
We find the leaves on a fasciated branch dying before those on the rest of the tree. On the Balsam Fir, an evergreen, the leaves are wholly deciduous; on a deciduous ally, the larch, the leaves mature before the others. On other trees we find always the leaves enduring longer than those on the fasciated; we say the leaves on the latter have a lower vital power. In severe winters the branches in the fasciated wholly die in many cases, while those on other portions of the tree survive, and again we say, because they have a lower vital power. Precisely the same circumstances attend inflorescence. The leaves in their procession from a normal condition to petals lose this evidence of vitality in proportion to the degree of transformation. The petal dies before the sepal, the sepal before the bract, and the bract before the leaves in the general order of anthesin in a compound flower, though there are cases where, secondary causes coming into play, this rule would be reversed; but in a general way the soundness of the point would not be disputed.
From all these facts in analogy it might be said in addition to the points brought out in the paper of 1870 above cited, that "a fasciated branch is an imperfect and precocious attempt to enter on the flowering or reproductive stage".