42 



NOMENCLATURE. 



47. 



A leaf is called pinnated (pinnaiurri), when it consists of 

 several distinct leaves, which spring along the sides of a com- 

 mon leaf-stalk ; (Tab. VI. Fig. 11.) The common leaf- 

 stalk is called the petiolus communis, as also the axis and 

 rachis. 



Pinnated leaves are classed according to the position of the 

 individual leaflets [pinna). When these stand opposite to 

 one another (opposite pinnata), they are reckoned by pairs 

 (Jugum), and the leaves are said to be two-paired, three- 

 paired, four-paired, and so forth (bi- tri- quadri-jugd). At 

 other times, however, the leaflets alternate with one another 

 {alternatim pinnata). If the summit of the whole leaf termi- 

 nate with an unpaired leaflet, it is then said to be impari-pin- 

 natum : when there is no unpaired leaf on the point, the leaf 

 is said to be abruptly pinnated (abrupte pinnatum). 



When, between the proper side-leaves, smaller leaflets are 

 placed alternately, the whole leaf is said to be interrupted- 

 ly pinnate (inter? upte pinnatum), as in Agrimonia Eupato- 

 ria. When the side-leaves run into one another, the leaf is 

 called decursively pinnate ^decursive pinnatum'), as in Sca- 

 biosa alpina. 



48. 



When the common leaf-stalk is divided in two parts, it is 

 said generally to be doubly compound (decompositum) ; and 

 when the division of the leaf-stalk is threefold, it is said to be 

 super decompound (supra decompositum), as in Peucedanum 

 oflicinale. 



Doubly pinnated (bipinnatum), is a leaf, of which the com- 

 mon axis is again set forth with pinnated leaves, as in Athy- 

 rium Filix foemina. The leaves of the first order are then 

 called pinnae, or Jbliola partidlia ; the leaves of the second or- 

 der pinnula or Jbliola propria. 



Triply pinnate (triplicato-pinnatum or tripinnatum), is a 

 leaf of Avhich the common axis has a threefold subdivision. 



