214 Maine Agricultural Experiment Station. 1920. 



Festuca rubra, Holcus lanatus, Koeleria cristata, Lolium itali- 

 cum, Lolium perenne, Oryza sativa, Poa pratensis, Poa trivialis, 

 Poa compressa, Setaria germanica and Phalaris arundinacea. 



After the coleorhiza has fulfilled its functions it is in turn 

 broken through by the radicle. The radicle escapes from the 

 coleorhiza through a lateral opening below the apex of the cole- 

 orhiza. Under the pressure of the radicle the cells of the cole- 

 orhiza become detached and are pushed apart without being in- 

 jured. 



POLYEMBRYONY IN GRASSES. 



In the course of the present investigation the writer ob- 

 served polyembryony in Arrhenatherum elatius, Poa pratensis. 

 Poa nemoralis, and Poa compressa. 



Diembryony occurred most frequently in Poa pratensis, 

 (Fig. 43) with only two cases of fruits developing three em- 

 bryos. Two cases of diembryony have been observed in Poa 

 nemoralis and one case in Poa compressa. 



A particularly fine case of diembryony has been observed in 

 Arrhenatherum elatius. (See Fig. 44.) The individual seed- 

 lings were equally well developed and were united at the base 

 of the hypocotyl possessing separate normal organs. As will be 

 seen from Fig. 44 the emergence of the seedlings out of the 

 glumes occurred in an abnormal manner, but their subsequent 

 development was normal. It may be stated in this connection 

 that in practically all cases of polyembryony the radicles emerged 

 abnormally from the glumes. 



Abnormal Germination as a Possible Source of Errors in 

 Recording Results of Germination Tests. 



From a practical point of view some of the results of this 

 investigation may have some significance in connection with the 

 determination of the viability of grass seeds as determined by 

 the germination test. The seeds of certain grasses are rather 

 exacting as to conditions of germination, and the question of 

 the influence of temperature, light and other physiological fac- 

 tors upon the germination of grass seeds still constitutes, an. im- 

 portant problem, for research, It is then obviously important, 



