60 



OF THE COMPOUND LEAF. 



283. Pointed leaves. In regard to the termination of a loaf at its 

 apex, it may be acuminate, ending with a long, tapering point ; cuspi- 

 date, abruptly contracted to a sharp, slender point ; mucronatr, tipped 

 with a spiny point ; acute, simply ending witli an angle ; obtuse, rounded 

 at the point. 



284. Pointless leaves. Or the leaf may end without a point, 

 being truncate, us if cut square off; retuse, with a rounded end slightly 

 depressed where the point should bo ; emarginate, having a small notch 

 at the end ; ohcordate, inversely heart-shaped, having a deep indentation 

 at the end.' 



OF THE COMPOUND LEAF. 



285. Theory. If wo conceive of a simple leaf becoming a cjn- 

 pound one, on the principle of " deficiency of tissue between the vein?,'' 

 it will bo evident that the same forms of venation are represented by 

 the branching petioles of the latter as by the veins of .the former. 

 The number and arrangement of the parts will therefore in like man- 

 ner correspond with the mode of venation. 



286. Leaflets. The divisions of a compound leaf are called to/?r/.s, 

 and the same distinction of outline, margin, &c., occur in them as in 

 simple leaves. ThQ petiohdes of the leaflets may or may not be articu- 

 lated to the main petiole, or rachis, as it is called. 



167 161 159 160 15S 



Compound leaves. 167, Trifolium i-apciis. 158, Dcsmodium rotundifolium. 160, Qlotidinm. 

 161, Cassia. 1.59, Agrimonia. 



287. PiNNATELY COMPOUND. From the pinnato-voinod arrangement 

 we may liave the pinnate leaf, v,'l-er." the petiole (midvcin) bears a row 

 of leaflets on each side, either seesile ox petiolulate, generally equal in 



