266 



WILLIAM H. LAMB 



The Bambuseae, according to the Besseyan classification,- 2 have 

 given rise to three lines of development beginning respectively, 

 with the Festuceae, the Phalarideae and the Andropogoneae. 

 These three lines of development, which for convenience we 

 will designate as the Festucean Line, the Phalaridean Line, and 

 the Andropogonean Line, have given rise to the other tribes, as 

 indicated in the accompanying figure, which also shows a dia- 

 grammatic sketch of the spikelet, the inflorescence, and the flower 

 of one genus in each tribe. Following is a list of the genera 

 which have been selected to typify each tribe: 



THE FESTUCEAN LINE 



The Festucean Line is characterized by having spikelets with 

 larger flowers at the base while in the other two lines the spike- 

 lets are with larger flowers at the top. 



Beginning with the Festuceae, we find grasses with from two 

 to many flowers in a spikelet, awnless or with a terminal awn, 

 and with inflorescence a panicle or sometimes a raceme. 



The Agrostideae have come in a direct line from the Festuceae 

 by a reduction of the number of flowers in the spikelet to one. 

 Sometimes, as we have illustrated in Calamagrostis, a small stalk 

 or rachilla is found which is to be regarded as a vestige of a sec- 



2 I wish to acknowledge my indebtedness to Dr. Charles E. Bessey, Univer- 

 sity of Nebraska, whose lectures in systematic botany have been of great assist- 

 ance in the preparation of this paper. 



