28 



PART I. ORGANOGRAPHY. 



plan, the common form observed in Monocotyledons, as Grasses, 

 Palms, Lilies, etc.; and the reticulate, or netted-veined plan, the 



Fig. 59. 



Fig. 58. 



Fig. 58. — The leaf of Gloriosa; a basi-nerved leaf. 

 Fig. 59. — The leaf of a species of Palm; a palmi- 

 nerved leaf. 



type which prevails in Dicotyledonous 

 plants, such as the Roses, Maples, 

 Oaks, etc. 



Among nerved leaves three dif- 

 ferent modifications are observed : 



(1) The basi-nerved, a form in which 

 the veins run nearly parallel to each 

 other from the base to the apex of the 

 leaf. Such leaves incline to elongated forms, and the type is 

 well illustrated in most grasses, and in the Gloriosa Lily, Fig. 58. 



(2) The palmi-nerved leaf, in which the veins are straight and 

 radiate from the petiole to the margin of the blade. Such 

 leaves incline to rounded forms. The type is illustrated in the 

 leaf of the Fan Palm, Fig. 59. (3) The pinni-nerved leaf, in 

 which there is a mid-rib or vein running from the base to the 

 apex of the leaf, and straight or somewhat curved veins running 

 from this, nearly parallel to each other, to the margin, as seen 

 in the Banana and the Calla (Richardia ^Ethiopica), Fig. 60. 



