DEFINITIONS OF TERMS 13 



present and exstipellate when they are absent, the words corresponding 

 to stipulate and exstipulate as applied to the entire leaf. 



Simple leaves as to their margins may be entire when the margin is a 

 continuous even line, without teeth or notches; serrate when cut into 

 sharp teeth pointing forward like the teeth of a saw; dentate or simply 

 toothed when the teeth are sharp and point outward, not forward; denticu- 

 late, diminutive of dentate; crenate when the teeth are rounded; crenulate, 

 diminutive of crenate ; repand or undulate when the margin forms a wavy 

 'line bending gently inward and outward; sinuate when the margin is 

 strongly undulate; incised or cut when cut into deep, sharp, irregular teeth ;^ 

 lobed when deeply cut, but the incisions do iiot reach much more than 

 h^tfissai to the midrib;' cleft, nearly the same as lobed, but the incisions 

 extending mor e than half-w ay to the midrib; parted when the divisions 

 extend nearly to the midr ib; and divided when they extend quite to it. 

 According to the number of lobes, clefts, etc., leaves may be S-lobed, 5-cleft, 

 many-cleft, etc. 



■'■" siniple leaves the method of division corresponds to the venation; in 

 pinnately-veined leaves the incisions all, point toward the midrib, and in 

 palmately veined ones they point toward the apex of the petiole. 



According to the degree of division we may have in pinnately veined 

 leaves, pinnately-lobed, pinnately-cleft, or pinnatifid, pinnately-parted, and 

 pinnately-divided or pinnatisect leaves, and in palmately veined leaves the 

 same combinations, with palmately substituted for pinnately. / 



The number of the lobes or divisions is frequently used, and we may 

 have palmately S-lobed, -S-cleft or trifd, -S-parted leaves, etc., and with 

 higher nmnbers palmately 5-lobed, -many-lobed, -many-cleft or multifid, etc. 

 The same combinations are made with the substitution of pinnate for 

 palmate. 



In compound leaves the separate parts, corresponding to the lobes, 

 divisions, etc., of simple leaves, are called leaflets. There are two principal 

 kinds, corresponding to the principal kinds of division in simple leaves, 

 pinnately compound and palmately compound. 



Pinnate leaves_are those where the leaflets are attached along the sides 

 of a main stalk or rachis, the leaflets corresponding to the lobes of a 

 simple, pinnately lobed leaf. When there is an odd or end leaflet, such 

 leaves are termed uneven pinnate, odd-pinnate, or imparipinnate; when 

 there is no odd terminal leaflet they are termed evenly or abruptly pinnate. . 

 Simp le pinnate leaves are those with a double row of leaflets; twice pinnate 

 or 2-pinnate leaves are those where the rachis bears branches, the branches . 

 bearing "the leaves, in which cases the branches are termed pinnae; the 

 division may be carried still further and we may have S- or tripinnate,i- 

 or quadripinnate or pinnately decompound leaVes, etc. 



In galmately compound leaves we may have the division carried further 

 in twice palmate, or when the division is in three's, twice ternate or 

 biternate; if the division goes still further it is called palmately decompound. 



AJ to the number of leaflets they may be few! to many ; when only one, 

 as in the orange, the leaves are called 1-foliolate, or unifoliolate; when 2, 

 2-foliolate, or bifoliolate; when 3, 3-foliolate, or trifoliolate, etc., and these 

 terms are used with both pinnately and palmately. compound leaves, such 

 as pinnately 5-foliolate, palmately trifoliolate, etc. In pinnate leaves the 

 terms 2- or bijugate, S- or trijugate, multijugate, (juga— -pairs) etc., are 

 used to express the number of pairs of leaflets, pinnae, etc. 



