120 STRUCTURAL BOTANY. [102,103. 



leaf, illustrating the gradual transition of leaves from, 

 simple to compound in all stages. The leaves of 

 the Honey-locust and Coffee-tree (Gymnocladus) often 

 afford curious and instructive examples (362). 



305. A Hternate leaf is formed when the leaflets 

 of a ternate leaf give place themselves to ternate 

 leaves (359), and triternate when the leaflets of a 

 biternate leaf again give place to ternate leaves. 



361 

 Compound leaves. 359, Clematis. 360, Erigenia bulbosa. 361, Acacia. 362, Honey -locust. 



306. Palmately compound. The palmate venation 

 has also its peculiar forms of compound leaves, as ter- 

 nate, quinate, septenate, etc., according to the number 

 of leaflets which arise together from the summit of 

 the petiole. Ternate leaves of this venation are to be 

 carefully distinguished from those of the pinnate plan. 

 The palmately ternate leaf consists of three leaflets, 

 which are either all sessile or stalked alike ; the pin- 

 nately ternate has the terminal leaflet raised above the 

 other two on the prolonged rachis (354, 355). 



307. Apex. In regard to the termination of a leaf 

 or leaflet at its apex, it may be acuminate, ending 



