14 



NA TURE 



{Nov. 6, ii 



tions, but the length of time during which they are avail- 

 able is too short to allow annuals to profit by a sufficiently 

 large aggregate to enable them to mature their seeds. 

 Before they can accomplish their purpose, they are over- 

 taken by frost and their activity is put a stop to. The 

 energy of perennials, it is true, may be checked in the 

 same manner, but they have been enabled, before the evil 

 day arrived, to lay up stores of nutriment available for use 

 when the increasing heat and light of the following year 

 shall once more quicken their activity. The work to be 

 done is spread over two or more seasons instead of 

 one, and the chances of success are thus correspond- 

 ingly enhanced. But if we suppose the conditions 

 to be uniformly and continuously favourable, the 

 abrupt cessation ' of growth will no longer be 

 manifest, the annual will cease to be an annual, the 

 perennial will not die down in winter, the growing points 

 of the buds will not incase themselves in scales, vegetation 

 will be continuous. Such halcyon conditions find their 

 nearest realisation in moist equatorial climates like that 

 of the Malay peninsula and adjacent islands. But even 

 there the realisation is not perfect. Something happens to 

 disturb the balance ; and even if the conditions are 

 generally uniform there is always the idiosyncrasy of 

 individual plants to form a disturbing factor. Again, such 

 conditions, though favourable to the continuance of 

 vegetation, are less propitious to the establishment of 

 fructification. The formation of stem, leaf, flower, even 

 of fruit, is one thing, the maturation of the seed and of 

 the embryo-plant within it is another ; and the conditions 

 propitious to either are correspondingly different. The 

 ripe seed makes in proportion larger demands on the 

 plastic matters formed as a result of metabolism, and has 

 almost invariably the same composition according to its 

 species, but this cannot be said with equal truth of any 

 other part of the plant. 



Again, the conditions for growth, that is, mere increase 

 in bulk, are different, in degree at least, from those which 

 favour progressive development or metamorphosis. 

 Speaking in general terms, it may be said that vegetation 

 approaches its end where fructification shows signs of 

 commencement. There is indeed no fixed line of demar- 

 cation to be drawn, but while morphologically there are 

 gradations and intermediate forms, physiologically there 

 are also transitions, and periods of instability. It is easy 

 to understand how this happens, and how it is the diver- 

 gences are not greater. These matters indeed partake so 

 much of the nature of truisms, that some apology might 

 almost be needed for insisting on them, were it not that 

 they are absolutely essential for the due comprehension of 

 the phenomena of untimely blooming. 



It is also desirable to draw attention to the fact that there 

 is naturally a wide range in the period during which vital 

 activity manifests itself even in individuals of the same 

 species, and as these individuals vary in colour, stature, &c, 

 even when derived from the same stock, so others may 

 vary in their " time-rates." This is specially noticeable in 

 the case of the horse-chestnut, and is perhaps more often 

 manifest in the form of precocious development in spring 

 than in that of tardy growth in autumn. In most cases 

 the plant has to attain a certain age before it produces 

 flowers, but occasionally we find individuals so precocious 

 that they are scarce out of the seed before they burst into 

 flower. A cocoa-nut has thus been seen in flower while 

 the husk of the fruit was still attached to it. Gardeners, 

 according to their requirements, have freely availed them- 

 selves of these individual differences by selecting for per- 

 petuation late or early varieties. The whole subject of 

 the " chronometry of life," it may here be mentioned, 

 formed the text of a valuable lecture by Sir James Paget, 

 at the Royal Institution, many years ago. 



Cases of unseasonable blossoming may be ranged under 

 three heads, according as growth and development are : 

 (i) prolonged beyond the ordinary time ; (2) premature or 



manifested aforetime ; (3) renewed after a short interval 

 of arrest. Categories (2) and (3) differ in detail rather than 

 in essence, as will be explained further on. 



Taking the cases of continuous or prolonged growth 

 first, it is easy to see that many of them are due to a 

 continuance of favourable conditions. A long spell of 

 summer without excessive heat or drought will insure a 

 longer period of blooming ; flower will succeed to flower so 

 long as the weather and the natural changes in the tissues 

 of the plant, according to age, are held in abeyance. How 

 small are the exigencies of some plants in these matters 

 may be illustrated by the fact that there are few days in the 

 year when a daisy or a white deadnettle may not be 

 found in bloom, at least in the southern half of England. 

 It is necessary, however, to introduce some qualification, 

 because one has only to look into one's garden to see 

 that in spite of apparently favourable conditions many 

 plants are not to be induced to continue blooming. 

 Although in duration perennial, in the matter of flower- 

 ing they behave as annuals. Something in their 

 organisation forbids the prolongation of the blooming 

 period. That this is so is at least rendered highly 

 probable by the circumstance that the same reticence is 

 exhibited under cultivation. As an illustration of an oppo- 

 site character, may be mentioned the prolongation of the 

 blooming period even under relatively adverse circum- 

 stances which has been brought about by the art and selec- 

 tion exercised by the gardener. Take roses, for instance, 

 only one of many that might be cited. Our fathers had 

 to be content with what we now call summer roses, roses 

 of great beauty and exquisite fragrance, but which they 

 must have wept to see " haste away so soon." Now- 

 adays, the case is very different, there is a whole legion of 

 so-called "hybrid perpetuals " marked in the catalogues of 

 the nurserymen as H.P. By their agency a second crop 

 of roses is assured, while some will continue in favour- 

 able seasons to expand their blooms in succession up to 

 Christmas. This prolongation of the flowering season has 

 been brought about by combining by means of hybridisa- 

 tion the robust qualities of European roses with the 

 continuous blooming tendencies of the Indian rose. 

 Many varieties of pear, the common laburnum, the 

 Wistaria, Weigela, the hybrid Berberis stenophylla, 

 some rhododendrons, currants {Ribcs), exhibit this 

 phenomenon, the flowers being produced on the ends of 

 more or less prolonged shoots, as strawberries under like 

 circumstances produce their flowers on the ends of the 

 " runners " of the year. 



The premature development of flowers in autumn has 

 a better title to be called unseasonable, because the 

 phenomenon is really due to the unfolding of flowers 

 which, under ordinary circumstances, would remain 

 passive till the following spring. There is not, as in the 

 former case, a new formation or a continuous growth, 

 but merely what the French appropriately caWJlei/raison 

 anticipte. And here for a moment it may be allowable to 

 call attention to an essay of Linnaeus entitled Prokpsis 

 Plantarum, little read nowadays, although based on facts, 

 and containing much that is still worthy of consideration. 

 For him a flower was a shoot with lateral outgrowths, a 

 morphological conception that would still satisfy a German 

 transcendentalist. But, further, this shoot and its out- 

 growths were supposed to represent the outcome of six 

 ordinary years' work contracted into one. A flower 

 was, according to this theory, a shoot in which the 

 differentiation of parts instead of being spread over six 

 years was hurried on and completed within one season. 

 For Linnaeus leaves represented the work of one year, 

 bracts that of the following one, sepals of the third, petals 

 of the fourth, stamens of the fifth, and the pistil that of 

 the sixth year. It is not necessary to discuss the mor- 

 phological aspects of this theory, but it is relevant to our 

 present purpose because it emphasises the relation of 

 leaf-shoot to flower — a relation enunciated about the same 



