367 



Mr. Thomas Twining, jun., exhibited a large collection of cultivated specimens 

 from Twickenham. A paper was read from Mr. R. S. Hill, being " An Enquiry into 

 Vegetable Morphology.'' 



Morphology is that division of Botany which takes cognizance of the various 

 changes which occur in the condition of the vegetable organs, both such as are nor- 

 mal, as the transmutation of leaves into the several floral organs, as well as such as 

 are abnormal, and occur only accidentally. 



Taking the above as the definition of the subject, we immediately see its divisibi- 

 lity into two heads ; the first of which treats of regular metamorphoses, which are con- 

 nected with the natural structure of all vegetables : while the second includes those 

 irregular or accidental metamorphoses, which result from an imperfect or redundant 

 perfonnance of the several changes noticed under the first head. These last influence 

 particular plants, or parts of plants, and occur only in occasional instances. To this 

 division belongs the consideration of double and other monstrous flowers. 



Of regular Metamorphosis. — The great principle of regular Morphology is, that the 

 various floral organs are but modifications of one common type, which is the leaf. 



Lindley endeavours to give to Linnaeus the credit of having been the author, or at 

 least of haviug suggested the idea of this great fundamental principle ; and in proof 

 of this opinion quotes passages from his ' Systema Naturae ' and ' Prolepsis Planta- 

 rum,' in which the theory is imperfectly hinted at. At his suggestion the subject does 

 not seem to have been taken up ; nor was it at all until Goethe published in 1770 his 

 work ' On Vegetable Metamorphosis.' With a knowledge of the character of his poe- 

 tical writings, it hardly need excite surprise that botanists of the day should have been 

 sceptical on a subject so new, and at first sight so opposed to the dictates of common 

 sense ; and that his work at the time should have been considered to partake of the 

 fanciful character of his poetry ; or that they should regard it more as a poetical dream 

 than as a sober philosophical truth, in connexion with a natural science. 



Leaves are in many instances entirely wanting, or exist only in the degenerated 

 forms of scales and spines. In these cases there is hardly any part of a plant which 

 is not capable of being modified and rendered capable of performing the functions of 

 leaves. For this purpose we find the excessive development of the stem which obtains 

 throughout lactaceous plants; also the stem is furnished with leafy wings or expan- 

 sions which run down its sides, as is seen in Acacia alata, &c. The petiole, in the 

 form of the phyllodium, frequently takes upon itself the ofiice of the leaf, as in most 

 of the Acacias from New Holland. The same functions are frequently discharged by 

 the peduncle, as in Ruscus, Asparagus, &c. ; and this appears to be the true charac- 

 ter of the leafy organs of Ferns, the true leaves of which exist in the degenerated form 

 of scales known by the name of ramenta. 



The evidence of the identity of bracteae with leaves is more apparent than that of 

 many of the other organs, for in very many plants they difi"er but little, except in size,, 

 from the original type, and indeed in almost every instance, even among those which 

 are highly coloured, as in many of the genus Salvia, we find presented a gradual tran- 

 sition from the fonn and colour of the leaf to an almost petaloid condition ; Salvia 

 splcHdens and Sclarea are both good examples of this. The position of these organs on 

 the axis shows clearly their close analogy to leaves, for they usually follow more or less 

 the normal position of the leaves of the species, whether alternate or opposite. The 

 calyx consists of a series of leaves arranged in a whorled manner round the axis, either 



