CHAP. CV.

t’ORYLA'CETE. yUE'RCUS.

182.5

destined to wither and drop off'as soon as their office of shedding the pollenis terminated; but if, before they have done so, they are seized and appro-priated by the fly, they become permanent, and remain so until the maggotwithin the gall ceases to feed. From this circumstance, it is evident that theflow of the sap is in the proportion to its consumption ; that ‘ bursting buds,lengthening shoots, expanding leaves, swelling fruit,’ or swelling galls, equallyattract currents of sap, and, in the last instance, even into a foreign channel ;proving what Du Petit Thouars, and other botanists, have long ago advancedas their opinion ; viz. that the growth of a tree is not caused by the motionof the sap, but the movement of the latteris caused by the distension of the variousmembers.” (./. Main in Gard. Mag., vol.xii. p. 708.) The artichoke gall, or oakstrobile (Jig. 1650.), is probably the “ oaknut ” of the ancients : it is about the size ofa filbert, and, from its closely imbricatedscales somewhat resembling a fir strobile oran artichoke, it has so been termed, (lieaum.

Mem., tom. iii. pi. 43. f. 1—12.) It is

produced by the Cynips quercus gemmae,and is a most beautiful foliose gall; for thedevelopement of the bud, although per-verted, not being wholly prevented, theleaves are gradually evolved. “ These galls,”says Professor Burnet, “ throw much lightupon the natural metamorphoses of plants,especially on the transition from leaves to flowers, by the abortion ofthe axis of the bud, and the leaves hence becoming whorled; and, whenthe axis of each leaf (that is, its petiole and midrib) becomes in like mannercurtailed, the gall assumes a still more florid form. Occasionally, in theoak, but more frequently in the willow, the gallic acid changes the ordinarygreen colour of the abortive leaves into a bright red, giving the preter-natural growth very much the appearance of a rose; and hence Sidix i?elix,in which this occurs, has been not inaptly called the ‘ Rose Willow.’ Thebedeguar, or hairy gall (Galla capillaris of the ancients), is a peculiar andvery beautiful species, though rather scarce, for which reason it was formerlymuch esteemed. In structure it is very similar to the bedeguar of the rose;and it is usually situated in the axils of the leaves. It is considered excellentas a styptic. Whether the ‘ oak wool,’ flocks of which were once so famedas wicks for lamps, but which, as Parkinson shrewdly observes, will not burn‘ without oyle or other unctuous matter, as Pliny saith it will,’ was the sameas our cottony or woolly gall, the description of the ancient Galla lanatarenders doubtful; for the flocks of wool are said to have been enveloped in ahard case; which structure is rather more analogous to that of our clusteredgalls, usually about six or seven in a group, and each the habitation of aseparate grub; as in them the little hard galls containing the insects areincluded in a soft and spongy, though not woolly, material, and are defendedexternally by a hard ligneous case: these may by some, however, be es-teemed the oak nuts, rather than the strobile one before alluded to.” (Amnen.Quer. in EidodenJ

The oak berries, described as “ sticking close to the body of the tree,”were, doubtless, the galls produced by the Cynips quercus ramuli, or C. q.corticis ; and the U'vas quercinse, or oak grapes, were, not improbably, theaggregation of similar galls, which are occasionally found upon the roots, orat the line of demarcation between root and stem, and which are produced bythe Cynips quercus radicis. We have been favoured by the Rev. W. T.Bree with a very fine specimen of this gall, which he discovered, on the 22dof February, 1837, on the root of an oak tree (just at the surface), and whichwas at that time inhabited by a number of the Cynips quercus radicis in the

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