SURFACE AND OUTLINE. 



83 



Hispid. A surface which is roughened 

 by the presence of numerous, closely set 

 wrinkles is Rugose. When a surface is 

 made up of small, blister-like elevations 



merely meet or overlap there without be- 

 coming connate (Fig. 385), giving us the 

 Open Sheath. 

 As to the attachment of the blade to the 



consisting of the arching interspaces be- petiole, the leaf is Peltate when this in- 



tween the veins it is Bullate (Fig. 392). 

 The opposite surface, containing the cav- 



sertion is intra-marginal through the con- 

 nation of the edges of basal lobes. A 



ities of the bullae, is called Cancellate peltate leaf may be Centrally (Fig. 390) 



or Eccentrically (Fig. 399) peltate. When 



(Fig. 393). When the hairy covering is 

 chiefly confined to the margin, presenting 

 itself in the form of a fringe of hairs, the 

 term Ciliate is applied (Fig. 391). 

 Finally it is to be noted whether the 

 veins or ribs, and which of them, are 

 prominent upon both sides or either side, 

 or whether, upon the contrary, they are 

 depressed (called Impressed) below the 

 general surface. At times a rib or vein 

 will not be impressed, but will yet be 

 channelled, so as to appear impressed 

 upon casual observation. A surface 

 which is marked by spots, differing in 

 color from the remainder of the surface, 

 is called Maculate. 



As to their attachment to the plant 

 stem, leaves are Sessile (Fig. 394) when 

 they possess no petiole. When a petiole 

 or a lamina has grown fast for a portion 

 of its length, to the plant stem, it is Ad- 

 nate (Fig. 395). One whose base is 

 heart-shaped and surrounds the plant 

 stem, whether growing fast to it or not, 

 Is called Amplexicaul or Clasping (Fig. 

 396). When the basal lobes of a clasping 

 leaf entirely surround the stem and be- 

 come connate upon the other side, so that 

 the stem appears to be growing up 

 through a perforation in the leaf, the leaf 

 is called Ferfoliate (Fig. 397), When op- 

 posite leaves are connate by their bases 

 they are called Connate or Connate-per- 

 foliate (Fig. 398). When the base of the 

 leaf has its ventral surface brought into 

 contact with and surrounding the stem 

 it is called Sheathing (Figs. 385 and 386). 

 When the bases of sheathing leaves clasp 

 the stem in such a manner as to present 

 a V-shape in transverse section, and one 

 is superposed upon another in the same 

 manner, they are called Equitaut. Leaf 

 sheaths are divided into two classes, ac- 

 cording to whether the edges are connate 



the petiole changes so gradually into the 

 lamina that it is impossible to say where 

 one begins and the other ends, we say 

 they are Continuous (Fig. 400). When 

 the margin of a blade is continued down- 

 ward along the sides of a petiole, the lat- 

 ter is called Margined (Fig. 401). When 

 these margins are manifestly herbaceous 

 it is sometimes distinguished as being 

 Winged, although this application of tie 



term is not to be commended. Some of* 

 the terms here given connect this aspect 

 of leaf classification with that which fol- 

 lows in reference to the distinctive form 

 of the base. 



By the Outline of the leaf, we refer to 

 the general form of its margin, whether 

 that be entire, or not. If not, then the 

 general form of an outline is formed by 

 connecting the extreme points of its mar- 

 gin with one another (Fig. 402, an obo- 

 vate outline). It matters not, therefore, 

 whether a leaf be entire, toothed, lobed 

 or parted, or even if it be entirely com- 

 pound or decompound, its outline will be 

 the same provided a line connecting its 

 extreme marginal points with one an- 

 other possess a given form. The forms 

 ot* leaves on this basis may be divided 

 into three general classes— (a) those 

 broadest at or about the middle, (b) those 

 broadest at some point above the middle, 

 (c) those broadest at some point below 

 the middle. Of the first class, beginning 

 with the narrowest, we have the Capil- 

 lary or Hair-like forms, the Filiform or 

 Thread-shaped (Fig. 403), the Acerose or 

 Needle-shaped (Fig. 404), as those of the 

 pine, and the Linear or Ribbon-shaped 

 (Fig. 405), all of which are so elongated 

 that they present the appearance of being 

 about of uniform width throughout A 

 leaf similar to but shorter than the 



upon the opposite sides of the stem (Fig. linear in proportion to its breadth, with- 

 38G), giving us the Closed Sheath, or out regard to the character of its apex or 



