XX PRELIMINARY DISCOURSES. 



the process, degentrescence i. e. a sort of degeneracy, or habitually 

 stunted growth, Thus, in some plants, we find the true stem-leaves 

 habitually curtailed of their fair proportions, compound leaves 

 being reduced to simple disks, or dilated petioles, called phyllodia, 

 simple leaves starved into mere needle-like processes, and stipules 

 shrunk into prickles ; while even woody branches, under a similar 

 privation, often appear in the character of true thorns. By taking 

 this view of the vegetable economy, we are not only led to contem- 

 plate the various modifications with great interest but are put 

 completely on our guard against any illusion, or misapprehension of 

 the real nature of apparent irregularities, or so-called anomalies. 

 We know that the proper place to find a leaf, is at the nodes: "We 

 shall generally find one there. It will sometimes be very small 

 sometimes reduced to a mere scale, or midrib or it may even be 

 entirely wanting ; but that's the place to look for it, and if we find 

 any thing occupying the normal position of a leaf, or stipule, we shall 

 be prepared to understand its true character. So of the other organs. 

 Whatever strange-looking appendage we may find in the proper 

 position of any organ, we shall at once comprehend, that it is some 

 disguised form, or modification, of that particular organ.* 



* This view of the subject, I would wish to impress strongly, and distinctly, on 

 the mind of the Botanical Student. Every organ of a plant being liable to modi- 

 fication, we must take care not to be misled by appearances ; but be constantly 

 suspicious of all disguises, or deviations from regular structure, and symmetry. 

 The clew to real character as intimated in the text will be afforded by the posi- 

 tion of an organ. In the grape-vine, for example, those anomalous organs, called 

 tendrils, will be found occupying the normal position of flowering branches; and 

 observation has shown that they are, in fact, nothing but abortive or metamor < 

 phosed racemes. They may be often seen in the transition state, some of the 

 subdivisions of the tendrils actually l>e&ringjlou>ers. Prof. DE CANDOLLE even con- 

 sidered the main stems of twining plants as partaking of the character, and verg- 

 ing towards the condition, of tendrils ; and his opinion is rendered plausible by 

 what we see in many climbers. In some species of Clematis, and in Adltimia, the 

 petioles, or footstalks of the leaves, perform the office; and in the vetches, or Pea 

 tribe, the common petioles usually terminate in real tendrils. In certain leafless 

 plants such as the Opuntia, or prickly Pear, and some species of Phyllanthus, 

 the stem assumes the flat, dilated figure and, to some extent, actually performs 

 the function of leaves : But, with the aid of our Theory, there is no danger of 

 mistaking the real character of any of these " counterfeit presentments." 



The change of calyx, and receptacle, into apparent fruit by reason of the 

 copious development of cellular tissue, in those organs, is not an unusual occur- 

 rence. Their position, however, in relation to the other parts of the flower, ren- 

 ders the circumstance perfectly intelligible.. The gradual conversion of pistils, 

 or carpels, into the countless varieties of mature fruit, is readily explained by 

 this development of tissues. In their early, rudimental stage, at the opening of 

 the flowers, the texture of the carpels is very similar in all plants; but, during 

 their growth, and progress to maturity, a great change is effected in the different 



