INTRODUCTORY LESSONS. 



XIX 



"base of ilie leaf. Fig. 40 represents a pinnately lobed leaf; Fig. 43, 

 palmately lobed. When leaves are deeplj^ lobed, as in Figures 41 and 44, 

 they are said to be Parted. Divided leaves are cut quite to the midrib if 

 pinnately divided, or to the end of the petiole when palmately divided. 

 Cleft leaves have the sinuses between the lobes sharp as in Fig. 38. When 

 leaves are pinnately cleft about half way to the midrib they are said to be 

 Pinnatifid. If the lobes are j)innatifid it is described as Bipinnatifid. It 

 is common to give the number of lobes in the descriptive phrase, as pin- 

 nately nine-lobed (Fig. 40); pinnately eleven-parted (Fig. 41); palmately 

 five-lobed (Fig. 43); palmately five-parted (Fig. 44). 



Compound Leaves have distinctly separate leaflets usually jointed 

 to a common petiole, just as simple leaves are jointed to the stem. A leaf 



along opposite sides of the petiole 

 (Fig. 42); Palmate, if they all grow 

 from the end of the petiole (Fig. 

 46). Fig. 45 represents a pinnatehj 

 S-fuliolale leaf; Fig. 46, palmately 

 Z-foliolate. When there is no odd 

 leaflet at the end the leaf is ab- 

 ruptly pinnate. Leaves may be 

 twice, thrice, etc., compound, that 

 is, the leaflets may be compound 

 as in some acacias. 



Bracts are leaves among flow- 

 ers, or small undeveloped leaves 

 anywhere on the stem. 



Stipules may be adnate to 45. Pinnately S-foliolate leaf of Bur-clover, with 



. n .-, ;• 1 • ji small stipules. 46. Falmatelvor digitately 3-foliolate 



the base OI the J)etlOle, as in the leaf of a true clover, the broad adnate stipules lacerate. 



rose and clover (Figures 45, 46); they may grow on the stem; or, as in 

 some plants of the Buckwheat Family the stipules form a sheath surround-, 

 ingthe stem at the base of the petiole. Do not mistake the first leaves 

 of a growing axillary bud for stipules. 



Venation of Leaves. All the leaves thus far described are said 

 to be Netled-veined or Reticulated, because their skeletons of wood fiber 



