524 CONSERVATIVE ORGANS. [LECT. X. 



thrice paired (tergeminatum), when the leaf re- 

 sembles the twice paired in its petiolar divisions, 

 and has besides a third pair of leaflets at the point 

 where the secondary petioles originate, as in Mi- 

 mosa tergemina, Q3; but if the common foot- 

 stalk supports three secondary petioles on its apex, 

 and each of these support three leaflets, then the 

 leaf is termed doubly tern ate (biternatum, dupli- 

 cato-ternatum) , Q4. 



A leaf is termed doubly pinnate (bipinnatum), 

 when the secondary petioles are arranged in pairs 

 on the common petiole, and each secondary petiole 

 is pinnate, or displays the characters of the simply 

 pinnate leaf, Q5 ; it is conjugated and pinnate 

 (conjugatum-pinnatum), when a common petiole 

 supports a single pair of secondary petioles, each 

 of which is pinnate, as in Mimosa purpurea, 96; 

 ternated and pinnate (ternatum-pinnatum) , when 

 the common petiole supports on its apex three pin- 

 nate leaflets, as in HofFmannsegia: and digitated 

 and pinnate (digitatum-pinnatum) , when the num- 

 ber of these exceed three, as in Mimosa pudica. 



The pedate leaf (folium pedatum) is general- 

 ly described as a decompound leaf, composed of 

 a common petiole divided at its summit into 

 two diverging branches, with an intermediate 

 leaflet, and each branch supporting two or 

 more lateral leaflets on their anterior edge; as 



