616 JLofidon Horticultural Society and Garden.. 



those portions of the atmospheric air which are necessary for elaborating 

 the sap, and for exhaling the gases of which it requires to be deprived. 

 Parts of a plant are often called leaves, which are, in fact, stems. The 

 professor exhibited a large branch of .ffuscus androgynus (a kind of 

 butcher's broom), apparently covered with handsome dark green leaves, 

 on the surface of which were numerous flowers. These, the pro- 

 fessor stated, were not really leaves, though nothing could, in shape, 

 texture, and colour, more strongly resemble what we are accustomed 

 to call by that name; but expanded branches, being all deficient in 

 that essential characteristic of true leaves, buds in the axils, and being, 

 of course, incapable of propagation. No portion of the branch of the 

 iZuscus, which he held in his hand, could, the professor observed, 

 be made to grow. Whether cut between the nodes, or being a part only 

 of the internodes, the effect would be exactly the same. The real leaves 

 of this plant are brown dry-looking scales, similar to those before de- 

 scribed as enclosing buds, and as being the abortive leaves of the preced- 

 ing year. To demonstrate this more clearly, Mr. Lindley exhibited a 

 stalk of .Kuscus androgynus (strongly resembling a large head of asparagus), 

 the branches of which were not expanded, and on which the brown leaves 

 were distinctly visible : in the axils of these leaves buds form in the usual 

 way. Flowers, and real leaves, also form on the surface of the leaf-like 

 branches. 



These are not the only instances in which other parts of a plant may be 

 mistaken for leaves. Sometimes the petiole or footstalk of the leaf ex- 

 pands till it becomes scarcely distinguishable from the leaf itself. This is 

 the case with the Dionse^a Muscipula (or fly-trap), the leaves of which, 

 properly so called, are those parts armed with spines, which collapse, and 

 enclose flies, or other insects, that may happen to touch them. The 

 fleshy parts, below these irritable leaves, are, in fact, only enlarged foot- 

 stalks. The Sarracenia (or side-saddle flower) is remarkable for the sin- 

 gular form of its leaf stalks, which are tubular, and hold water ; while the 

 iVepenthes (or pitcher plant) has a very singular dilation of the petiole, 

 which forms a tendril, occasionally enlarging into the semblance of a leaf, 

 and ending in a complete pitcher, furnished with a lid, which is the leaf 

 itself. 



Flowers areonlymodifications of leaves; or rather, morecorrectlyspeaking, 

 they are, in fact, metamorphosed branches ; there being no essential differ- 

 ence, in the eye of a botanist, between flower-buds and leaf-buds, and the 

 expansion of both being in effect the same. Every flower bud proceeds 

 from the axil of a leaf, called a bractea, or floral leaf. On examining a 

 flower perfect in all its parts (the professor exhibited a paeony), it will be 

 found that these bracteas divide the peduncle or footstalk of the flower, 

 from the branch or stem ; and that they sometimes form a single whorl, 

 joined together at their margins, and having the appearance of an outer 

 calyx. The flower, with its peduncle springing from these bracteas, is 

 exactly analogous to a branch springing from the axil of a leaf; the pedun- 

 cle answering to the branch, and the calyx, corolla, stamens, and pistil 

 being metamorphosed leaves. The flower buds being thus in effect the 

 same as leaf buds, are, like them, produced at regular distances, and from 

 alternate sides of the stem. The transformation of leaves into petals is 

 clearly shown in the formation of the common tulip. This flower has no 

 calyx, or, at least, none that can be distinguished from the corolla. It has 

 six leaves round its parts of fructification, which may be either called 

 petals or sepals ; or supposed to be three of each, but there is no clear 

 mark of distinction, unless that of the three inner growing from a separate 

 whorl be deemed, a sufficient one. The leaves on the stalk of the tulip, 

 or bracteas i are often partially coloured like the corolla, as though they 



