Germination of Grass-Fruits. 



211 



move away the caryopsis, enclosed in the lemma and palet, from 

 the sterile glumes. 



Asssociated with the abnormal germination is a marked 

 tendency to develop adventitious rootlets which spring from the 

 hypocotyl or mesocotyl. This tendency is a result of the retarda- 

 tion in the growth of the primary radicle and reaches its highest 

 degree in cases where the primary radicle becomes stunted and 

 dies off. The frequently observed stunting and dying off of the 

 radicle was found to be due to abnormal germination rather than 

 to deficient viability. 



In Table I is given the frequency occurrence of the normal 

 and abnormal germination of fruits of twenty grasses. From 

 this table the high percentage of abnormal germination in 

 Arrhenatherum, Poa nemoralis and Poa compressa, Holcus lan- 

 atus will be noted. This table also shows a varying percentage 

 of stunted or dead radicles, being highest with grass fruits which 

 in addition to the fertile glume are surrounded, at germination, 

 also by the sterile glumes. 



In view of the high percentage of abnormal germination it 

 became a matter of practical importance to determine whether 

 this phenomenon occurs under natural conditions of germina- 

 tion in the soil. With this end in view a series of germination 

 experiments were carried out with fruits of 9 grasses sown in 

 pots filled with soil, the results of which are given in Table 2. 



TABLE 2. 







Normal 



Abnormal 



Radicle died 





Number of 



Germination 



Germination 



off within 



Kind of Grass 



fruits 

 sown 







glumes 





Per eent 



of Germinate 



i Fruits 



Alopecurus pratensis 



400 



98.0 





1.7 



Arrhenatherum elatius 



100 



100.0 







Onosurus eristatus 



100 



100.0 







Dactylis glomerata 



100 



100.0 







ynstuca arundinaeea 



400 



99.0 



0.3 



0.6 



F u stuca ovina 



100 



100.0 







Holcus lanatus 



200 



90.0 



6.0 



3.0 



Lolium italicum 



200 



100.0 







Lolium perenne 



200 



96.8 



3.2 





The results presented in Table 2 show that under natural 

 conditions prevailing in the soil abnormal germination either 

 does not occur at all or only with a few grasses to a very slight 



