1 8 Plant Morphology. 



Ivcaves may be (i) simple or (2) compound. The separate di- 

 visions of a compound leaf are called leaflets. The leaflet may 

 be described by the same terms as the simple leaf. 



Compound leaves are of two principal kinds : — pinnately-com- 

 pound and palmately-compound, depending upon the arrange- 

 ment of the leaflets upon the primary petiole or midrib. Their 

 signification will be easily understood from the use of the same 

 words in expressing methods of venation. 



In addition to the modified leaves already studied in connection 

 with underground stems, the following peculiar forms of leaves 

 may be observed and sketched : — 



Begonia (Begonia sp). 



Onion (Allium sativum). 



Northern Pitcher Plant (Sarracenia purpurea). 



Holly (Ilex aquifolium). 



Flowering dogwood (Corn us florida). 



Read — Gray "Lessons" pp. 49-67. 



References — Gray " Structural Botany "pp. 85-118. 

 Bessey " Botany " pp. 144-148. 

 Bastin " College Botany " pp. 18-47. 



Phyllotaxy. (For difierent methods of leaf-arrangement see, 

 " Methods of Branching," p. 10). 



