Book I. ANOMALIES OF VEGETABLE DEVELOPEMENT. 179 



798. The nvt-gall is generated on the leaf of a species of oak that grows plentifully in the Levant, and 

 is so well known in commerce as to require no particular description. It is occasioned by the puncture of 

 the Cynips quercifolii, which deposits its egg in the substance of the leaf, by making a small perforation on 

 the under surface. Galls and tumors are to be found on the leaves of many plants ; and indeed almost all 

 leaves are liable to deformities, giving them a blistered, wrinkled, or curled appearance ; and often pro- 

 ducing disease. 



799. The excess or deficiency of leaves protruded in a group sometimes constitutes the anomaly, as in 

 the case of the trefoils. 



800. Sometimes in the naturalfigure of the leaf itself, as in asparagus officinalis, where they are bristle- 

 shaped; salsola kali, awl-shaped; and allium cepa, in which they are tubular, tapering to a point. 

 But one of the most remarkable anomalies of figure is that which occurs in the leaves of the genus Sarra- 

 cenia (fig. 43. b\ of which the lower portion is tubular, ascending, and approaching to funnel-shaped, or 

 rather pitcher-shaped reversed, with a flattened and concave limb attached by the one side to the orifice of 

 the tube, and constituting the upper portion of the leaf. Linnams, who was acquainted with this singularity 

 of structure, accounted for it by supposing that it was an institution of nature, meant for the purpose of 

 furnishing the plant with a supply of water, which it could thus catch and retain in the leaf. But as some 

 species of the genus do not readily admit water notwithstanding their capacity to retain it, this hypothesis 

 is regarded by Sir J. E. Smith as being extremely doubtful, who accordingly offers a different solution, 

 founded upon the following facts. An insect of the Sphex or Ichneumon kind, had been observed by one 

 of the gardeners of the botanic garden at Liverpool, to drag several large flies to a leaf of sarracenia, 

 adunca, and to force them into the tubular part of it On examination, the leaf was found to be about half 

 filled with water, in which the flies were now struggling; the other leaves were also examined, and were 

 found crammed with dead or drowning flies. The leaves of sarracenia purpurea are said to exhibit also 

 the same phenomena, and seem peculiarly well adapted to entrap and confine flies, by having the margin 

 beset with inverted hairs rendering the escape of such insects as may have accidentally fallen into the 

 watery tube, or are intentionally forced into it, impracticable ; so that the putrid exhalation from the dead 

 insect's contained in the leaf often offends the nostrils, even in passing near the plant. Hence Sir J. E. 

 Smith infers, that the growth of the plant is perhaps benefited by means of the air evolved by the dead 

 flies, which the water has been intended to tempt, and the leaves to entrap and retain. This ingenious 

 conjecture is no doubt sufficiently plausible as far as the plant may be affected ; but cannot be regarded as 

 quite satisfactoj-y till such time as it shall have been shown that the health of the plant is injured when 

 insects are prevented from approaching it. 



801. The celebrated nepenthes distillatoria {fig. 43. c) exhibits also an anomaly similar to that of sarracenia, 

 holding an ounce or two of a fluid which appears to be secreted from the leaf, and to be intended as a 

 lure to insects, which gain admission either by the spontaneous opening of the lid, or by forcibly raising it 

 themselves. The consequence is that they fall into the fluid and are drowned, no insect being capable 

 of living in it except a certain small squilla or shrimp, with a protuberant back, which, according to Hum- 

 phius, sometimes crawls into it and can live there. To this phenomenon Sir J. E. Smith applies the same 

 explication as above, which is of course liable to the same objection. 



802. The figure of the leaf ', however singular, is generally the same throughout the same individual, ex- 

 cept in the case of accidental deformity, and yet there are exceptions even to this rule. For sometimes 

 the lower leaves of a plant are entire while the upper leaves are divided, as occurs in a variety of mountain- 

 ous plants, such as burnet, saxifrage, anise, coriander ; and sometimes the lower leaves are divided while 

 the upper leaves are entire, as in the case of a variety of aquatics, particularly ranunculus aquaticus, in 

 which the lower leaves are capillary and immersed, and the upper leaves flat and circular, floating on the 

 surface of the water. But sometimes the dissimilitude of the leaves is still more remarkable. The Chi- 

 nese mulberry, and the Eucalyptus, has not two leaves alike in form on the whole plant. And lastly, there 

 are some plants, as in the case of the fungi, that are wholly destitute of leaves, and hence called 

 aphyllous ; while there are others, as in the case of the fuci, that seem to be wholly leaf. 



803. The principal anomaly of the Jloiver, is that by which one of its parts is unduly 

 augmented, to the exclusion or diminution of some of the rest. The flower is then said 

 to be luxuriant, and comprises the three following varieties : the multiplicate, the full, 

 and the proliferous flower. 



804. The multiplicate flower is sometimes, though rarelv, occasioned by an unusual multiplication of the 

 divisions of the calvx, as in dianthus caryophvllus, and some of the Alpine grasses. But the anomaly 

 most generally consists in the undue multiplication ot the divisions of the corolla, by the conversion of part 

 of the stamens into petals which is occasionallv to be met with both in monopetalous and polypetalous 

 flowers. It occurs but seldom, however, in flowers growing in their natural state and habit, though now 

 and then a double flower is met with even in such circumstances. 



805. The full flower is generally described to be that in which the divisions of the corolla are so mufti. 

 plied as to exclude the stamens and pistils wholly bv means of their conversion into petals ; which conver- 

 sion is most readilv effected in polvpetalous flowers, such as the tulip, poppy, pink, and ranunculus ; mo- 

 nopetalous flowers' seldom being found full. This complete metamorphosis is always either the effect of 

 cultivation, or of some concurrence of natural circumstances analogous to it ; and is indeed one of the 

 principal objects of the art of the florist; the beauty of the flower, according to general estimation, being 

 thus much augmented. In the full flower the stamens are almost always converted into petals, whence we 

 should perhaps infer their identitv of origin. But the pistil is often converted into a leaf, as may be seen 

 by inspecting the flower of the double-blossomed cherry, which generally protrudes from the centre a leat 

 in miniature. But a flower may become full also by the multi- 

 plication of the parts of the nectary, as is sometimes the case 

 in the genus Aquilegia, which produces full flowers in three 

 different ways by the multiplication of the petals to the exclu- 

 sion of the nectaries, by the multiplication of the nectaries to 

 the exclusion of the petals, and by the multiplication of the nec- 

 taries while the proper petals remain. There are also some pe- 

 culiarities in the manner in which compound flowers become 

 full. Radiated flowers become full sometimes by the multipli- 

 cation of the floscules of the ray to the exclusion of the floscules 

 of the disk, as in helianthus, anthemis, and centaurea ; and 

 sometimes by the multiplication of the floscules of the disk to 

 the exclusion of those of the ray, as in matricaria and bellis. 



806. The proliferous flower yflg. 60.) is that out of which 

 another flower or another shoot is produced. It is seldom 

 found but in flowers already full ; from the centre of which, 

 that is, from the ovarv or pistil, it sometimes happens that a 

 new flower and foot-stalk is produced, if the flower is simple, as 

 in the ranunculus, anemone, and pink ; or several flowers and 

 foot-stalks, issuing from the common calyx, if the flower is com- 

 pound, as in the daisy, hawkweed, and marigold ; or a new 

 umbel issuing from the centre of the ongmal umbel, it tne 



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