BOTANY. 



One variety of the holly has, in addition 

 to a yellow variegation, a beautiful tinge 

 of purple, but this is a rare instance. In 

 the amaranthus tricolor the leaves are 

 naturally adorned with most beautiful and 

 splendid colours, and some in other spe- 

 cies of the same genus with more uniform 

 and less vivid lints. 



The irritable nature of some leaves is 

 remarkable, not but that all leaves may 

 truly be said to possess irritability with 

 respect to light. The phenomena how- 

 ever to which we now allude are of the 

 most striking kind. The sensitive plant, 

 mimosa pudica, common in hot-houses, 

 when touched by any extraneous body, 

 folds up its leaves one after another, 

 while their foot-stalks droop as if dying. 

 ARer a while they recover themselves 

 again. Each leaf of the dionxa musci- 

 pula, or Venus's tiy-trap, is furnished 

 with a pair of toothed lobes, which, when 

 touched near the base, fold themselves 

 together, and imprison any insect that 

 may be in their way. It is presumed that 

 the air evolved by the body of the dead 

 insect may be wholesome to the plant, 

 for leaves are known to purify air im- 

 pregnated with carbonic acid gas. pro- 

 duced from the brea Jiing of animals or 

 the burning of a candle. The sarracenia, 

 of which several species from America 

 are now cultivated in our more curious 

 gardens, bears tubular leaves which retain 

 water in iheir hollows, and imprison in- 

 sects, whose putrefying bodies evidently 

 pro luce a quantity of bad air, and analo- 

 gy leads us to suppose that air is destined 

 to be serviceable 10 the constitution of 

 the vegetable. See Dr. Smith's Intro- 

 duction, page 195. 



Many important botanical distinctions 

 are founded upon the situations and forms 

 of leaves. These are explained by the 

 following terms. 



Folia radicalia, are radical leaves, as in 

 the primsose 



F. caulina, stem, leaves, and ramea, 

 branched leaves. Tiie situation ot the 

 latter is either alternate, opposite, scat- 

 tered, or clustered. Several leaves stand- 

 ing round a stem or branch are termed 

 verticillata, whorled : such as either ter. 

 nate, quaternate, or quinute, &.c. 



F. imbricata, imbricated, iie one over 

 the other like tiles upon a house. 



F. decusmtta, cross each :; ; her in pairs 

 alternately, as in many plant.-: " ii oppo- 

 site leaves. 



F. disticha, two-ranked, spread in two 

 directions like the yew. 



F. secunda, unilateral, lean all towards 



VOL. II. 



one side. Some leaves are erect, others 

 reflexed or recurved; but the greater 

 part spread more or less horizontally. A 

 few are obliquely twisted, and still fewer 

 are reversed, resupinata, what should be 

 the upper surface becoming the under, 

 as in the beautiful alstrxmeria. Curt. 

 Mag. 1. 139. 



F. petiolata, are such as stand on foot- 

 stalks; sessilia, sessile leaves, grow imme- 

 diately from the branch or root without 

 any stalk. 



F. peltata, peltate leaves, have the foot- 

 stalk inserted into their centre, like the 

 handle of a shield, to which the name al- 

 ludes, witness the common nasturtium 

 trapaeolum. 



F. amplexicaulia, clasp the stem or 

 branch with their base. 



F. decurrentia, run down the same part 

 in the form of a leafy border, as in many 

 thistles. 



F. connata are united at their base. 



F. perfoliala have the stem running 

 through them, as in hair's-ear, bupleurum 

 rotundifottum. 



Y.vuginanlia sheath the stem on each 

 other, as in most grasses. 



F. equitantiii clasp each other in two op- 

 posite rows, being compressed at the 

 base, as in many common species of iris. 



The form of leaves is either simple, as 

 in grasses, lilies, &c or compound, as in 

 parsley, elder, roses, &c. Simple leaves 

 are either Integra, undivided, like those 

 just mentioned, or lobed, like the vine, 

 holly-hock, and many others. 



The following forms of simple leaves 

 respect their outline only. 



Folium orbiculutum, as nearly circular 

 as possible, which is very rare. 



Subrotundum, roundish, is much more 

 common. 



Ovatwn, ovate, the shape of an egg, 

 ve; y frequent. 



Obovatum, obovate, the same figure, 

 with the broad end uppermost. 

 . Ellipticum or ovale, elliptical, or oval, 

 being broadest in the middle. 



Qblongwn, oblong, several times longer 

 than broad, without any very decided 

 form. 



Spatulatum, spatulate, of a roundish 

 figure, tapering into an oblong base. 



Cuneifoi-me, w edge-shaped, broad at the 

 summit, tapering down to the base. 



J.anceolatumi lanceolate, narrow, and 

 oblong, tapering towards each end, a ve- 

 ry common sort of leaf, as in willows. 



Lineare, linear, narrow, with parallel 

 sides, like most grasses. 



Jlcerosum, needle-shaped, linear, and 



I i 



