MONOCOTYLEDONS AND DICOTYLEDONS 



nuirgiii of the leaf, but forms a ^^ closed venation/*' so that 

 the leaves usually have an even {entire) margin. There 



are some notable exceptions 

 to this character. 



(4) Cyclic flowers trim- 

 crous. The *^ three-parted" 



Fig. 215. Two tj'pes of leaf venation: the figure to the left is from Solomon's seal, 

 a Monocotyledon, and shows the principal veins parallel, the very minute cross 

 veinlets being invisible to the naked eye; that to the right is from a willow, a 

 Dicotyledon, and shows netted veins, the main central vein (midrib) sending out 

 a series of parallel branches, wliich are connected with one auothcr by a network 

 of veinlets. — After Ettingshausen. 



flowers of cyclic Monocotyledons are quite characteristic, 

 but there are some trimerous Dicotyledons. 



Dicotijledojis. — (1) Embryo with lateral cotyledons and 

 terminal stem-tip. 



(2) Vascular bundles of stem forming a hollow cylinder 

 (Fig. 216, w). This means an annual increase iii tlie (liiim- 



