VIVIPAROUS PLANTS. 169 



The grasses most commonly affected in this manner 

 are Dadylis glomerata /, Poa bulbosa /, Poa annua /, 

 P. trivialis /, pratensis !, alpina /, angustifolia, and laxa, 



Fig, 81. Portion of panicle of Aira vimpara and separate floret. 



Gynosurus cristatus, Festuca nemoralis, F. ovina !, Ghj- 

 ceria fiuitans ! J Gl. aquatica, Aira alpina !, ccespitosa!, 

 Phleum phalaroides, Lolium perenne /, Alopecurus pra- 

 tensis /, Agrostis alba, Holcus mollis ! 



From an examination of the structure of viviparous 

 grasses Yon Mohl was led to the conclusion that the 

 lower palea is to be considered as a bract, and not a 

 perianthial leaf, because the base of the palea sur- 

 rounds the stem or axis of the spikelet entirely, and 

 both its margins cohere towards its lower extremity.^ 

 similar condition occurs not infrequently in 

 ^ohjgonum viviparum, and in JuncaceWf Cyperacece, &c. 



Cited in ' Annals Nat. Hist.,' 1845, vol. xv, p. 177. 



