ORGANS OF NrXEITION. 



163 



pari-jnnnate when it ends in a pair of leaflets or pinnse (Jl^. 332), 

 as in some species of Cassia, theMastich ^lant {PistaciaLenHscus), 



Fig. 335. 



Fig. 335. Bipinnate leaf of a species of Gleditschia.- 

 plnnate leaf. 



-Fig. 336. A tri- 



Logwood {HcBmatoxylum Campechianum), and Orohus tuherosus ; 

 it is interrwptedly pinnate {fig. 333) when the leaflets are of 

 diflPerent sizes, so that small pinnae are regularly or irregularly 

 intermixed with larger ones, as in the Potato and Silver Weed 

 {Potentilla anserina). "When the terminal leaflet of a pinnate 

 leaf is largest, and the rest gradually smaller as they approach 

 the base {fig. 334), it is lyrately pinnate; this leaf and the trud 

 lyrate (p. 154) are frequently confounded together by botanists, 

 and the two forms frequently run into each other, so that it 

 is by no means uncommon to find both on the same plant, as in 

 the common Turnip and Yellow Eocket. 

 m2 



