OUTLINES OF BOTANY. vii 



52. In a peltate leaf, the stalk, instead of proceeding from the lower edge of the blade, is 

 attached to the under surface, usually near the lower edge, but sometimes in the very centre of 

 the blade. The peltate leaf has usually , several principal nerves radiating from the point of 

 attachment, being, in fact, a cordate leaf, with the auricles united. 



53. All these modifications of division and form in the leaf pass so gradually one into the 

 other that it is often diifioult to say which term is the most applicable — whether the leaf be 

 toothed or lobed, divided or compound, oblong or lanceolate, obtuse or acute, etc. The choice of 

 the most apt expression will depend on the skill of the describer. 



54. Xieaves, when solid, Steins, Fruits, Tubers, and other parts of plants, when 

 not flattened like ordinary leaves, are 



setaceous or capillary, when very slender like bristles or hairs. 



acicular, when very slender, but stiff and pointed like needles. 



subulate, when rather thicker and firmer like awls. 



linear, when at least four times as long as thick ; oblong, when from about two to about four 

 times as long as thick, the terms having the same sense as when applied to flat surfaces. 



ovoid, when egg-shaped, with the broad end downwards, obovoid if the broad end is upwards ; 

 these terms corresponding to ovate and obovate shapes in flat surfaces. 



globular or spherical when corresponding to orbicular in a flat surface. Round applies 

 to both. 



turbinate, when shaped like a top. 



conical, when tapering upwards ; obconical whefl tapering downwards, if in both cases a 

 transverse section shows a circle. 



pyramidal, when tapering upwards ; obpyramidal, when tapering downwards, if in both oases 

 a transverse section shows a triangle or polygon. 



fusiform, or spindle-shaped, when tapering at both ends ; cylindrical, when not tapering at 

 either end, if in both oases the transverse section shows a circle, or sometimes irrespective of the 

 transverse shape. 



tenvte, when the transverse section is not angular ; trigonous, triquetrous, if the trailsverse 

 section shows a triangle, irrespective in both oases of longitudinal form. 



com/pressed, when more or less flattened laterally ; depressed, when more or less flattened 

 vertically, or at any rate at the top; obcompressed (in the achenes of Compositm), when flattened 

 from front to back. 



articulate or jointed, if at any period of their growth (usually when fully formed and 

 approaching their decay, or in the case of fruits when quite ripe) they separate, without tearing, 

 into two or more pieces placed end to end. The joints where they separate are called 

 articulations, each separate piece an article. The name of joint is, in common language, given 

 both to the articulation and the article, but more especially to the former. Some modern 

 botanists, however, propose to restrict it to the article, giving the name of joining to the 

 articulation. 



did/ymous, when slightly two-lobed, with rounded obtuse lobes. 



moniliform, or beaded, when much contracted at regular intervals, but not separating 

 spontaneously into artielete. 



55. In their consistence Ijeaves or other organs are 



fleshy, when thick and soft; succulent is generally used in the same sense, but implies the 

 presence of more juice. 



coriaceous, when firm and stiff, or very tough, of the consistence of leather. 



crustaceous, when firm and brittle. 



inerribranoue, when thin and not stiff. 



scarious or scariose, when very thin, more or less transparent and not green, yet rather stiff. 



56. The terms applied botanically to the consistence of solids are those in general use in 

 common language. 



57. The mode in which unexpanded leaves are disposed in the leaf-bud is called their 

 vernation vrcefoUation; it varies considerably, and technical terms have been proposed to 

 express some of its varieties, but it has been hitherto rarely noticed in descriptive botany. 



§ 6. Scales, Bracts, and Stipules. 



58. Scales (Squamce) are leaves very much reduced in size, usually sessile, seldom green 

 or capable of performing the respiratory functions of leaves. In other words, they are organs 

 resembling leaves in their position on the plant, but differing in size, colour, texture, and 

 functions. They are most frequent on the stock of perennial plants, or at the base of annual 

 branches, especially on the buds of future shoots, when they serve apparently to protect the 

 dormant living germ from the rigour of winter. In the latter case they are usually short, 

 broad, close together, and more or less imbricated, that is, overlapping each other like the tiles 

 of a roof. It is this arrangement, as well as their usual shape that has suggested the name of 

 8caZes, borrowed from the scales of a fish. Imbricated scales, bracts, or leaves, are said to be 

 squarrose, when their tips are pointed and very spreading or recurved. 



