DEFINITIONS OP TERMS 11 



onion, garlic, etc., and those where the scales are thick and narrow are 

 called scaly bulbs. 



As to the arrangement of branches and leaves, they are opposite when 

 two are borne at the same node, from opposite sides of the* stem; whofled 

 or verticillate when, three- or more are borne at the same node, arranged 

 regularly around the stem; fascicled or fasciculate when two or more 

 are borne at the -same node on the same side of the stem; alternate when 

 one is borne at each node on one side, and the next above or .below on 

 the opposite side of the stem; distichous when regularly arranged one 

 above another in two opposite rows; and seeund when all are turned 

 toward, one side. 



THE LEAVES. — A typical complete leaf consists of the blade or lamina, 

 tiie broad thin part of ordinary leaves, the petiole or leaf-stalk, and a 

 pair of stipules, variously shaped appendages at the base of the leaf-stalk 

 or at the nodes, which may be leaf-like, scale-like, -or even represented 

 by sheaths or by spines. Stipules are frequently wanting, such plaints 

 being then termed exstipulate. The end by which the leaf, or any other 

 part of a plant is attached, is called the base; the opposite or free end, 

 the apex. 



The petiole or leaf-stalk is frequently wanting, the leaves being then 

 called sessile. When the leaf-base clasps the stem it is called amplexicaul 

 or stem-clasping; when the lobes meet around the stem so that the blade 

 appears as though it were pierced by the stem, it is called perfoliate; 

 when the ■ edges of the leaf extend downward along the stem as ridges 

 or wings it is called decurrent; when the base of the blade or the petiole 

 forms a more or less closed vertical cylinder surrounding the stem, it is 

 called sheathing. 



When the leaves are inserted on a stem or branch, they are termed. 

 cauUne; when they or the flowers are borne on the roots or rhizomes or 

 very close to the base of the stem, they are termed radical. Radical 

 leaves that spread in a circle on the ground forming a rosette are called 

 rosulate. 



Leaves are composed of a framework, consisting of ribs and veins , 

 and of the softer tissue. When there is only one main vein much 

 stronger than the others it is called the midrib; the primary divisions 

 on each side are called the lateral veins or nsrues, and the ultimate 

 divisions the veinleta, or nervules. In cases where several equally strong' 

 veins radiate from the top of the petiole, they are tended palmately, or 

 digitately nerved or veined, or "in peltate leaves radiately nerved. In 

 palmately nerved leaves, where the veins all -start from the base, they 

 are called 3-nerved, 5-nerved, etc., according to the number of nerves, 

 but . when some start just above the base they are called S-plinerved, 

 5-pUnervcd, etc. 



Venation is the term applied to the method of arrangement of the 

 veins; there are two principal 'kinAs, parallel-veined and netted-veined 

 or reticulate. In parallel-veined leaves the whole frame work consists of 

 slender ribs or veins that run parallel to each other,, either from the 

 base to the apex, or from the midrib to the margins, not dividing and 

 subdividing and forming meshes. In netted-veined or reticulate leaves 

 the veins branch and rebranch into finer and finer veinlets which unite 

 with each other to form meshes; this network of veins is usually spoken 

 of as the reticulations. Somietimes the nerves are so obscured by other 



