656 GEAMINB^. 



ADDITIONAL REMARKS on the Fertilisation of Geamine^, 

 in continuation of the statements at page 634 : — 



Dr. Hermann Miiller, in his work entitled " Die Befruchtung tier 

 Bhimen durch Insekten," has the following remarks : — 



"The whole family of Graminese consists of plants with very 

 marked wind-flowers. I have repeatedly seen, however, a small dip- 

 terous fly, Melanostoma mellina L., occupied with its mouth on the 

 anthers of difierent species {Antlioxanthvm, odoratum, Poa annua, 

 Festuca pratensis), probably consuming pollen grains which had re- 

 mained sticking in them. Many Graminese are protogynous. For 

 example, Anthoxanthum odoratum, Alopecurus pratensit, Na/rdus striata. 

 Oryna clandestina is remarkable for its kleistogamous (xXiigTos, closed, 

 yd/iog, wedding) flowers. 



" In Secale cereale (Rye) the flowers have the anthers and stigmas 

 matured simultaneously ; they open widely, and allow both sexual 

 organs freely to project. Cross-fertilisation can thus be efiected 

 through the wind on the most extensive scale. 



" In Tritieum vulgare (Wheat) the flowers, the stamens, and stig- 

 mas are likewise simultaneously matured ; they only half open them- 

 selves, and that for only a quarter of an hour, again hermetically to 

 close. The opening takes place suddenly, with immediate and com- 

 plete scattering of the pollen, about a third part of which goes into 

 the same flower, and two-thirds are carried out by the emerging 

 anthers. Cross-fertilisation by the wind can thus take place, only to 

 a much more limited extent. Self-fertilisation, according to Delpino's 

 experiments, produces good fruit. Since each flower remains open 

 for only a quarter of an hour, while the blossoming lasts four days, 

 only a very small number of the flowers are open at once. 



" In Hordmm vulgare or hexastichum (6-rowed Barley or Bere) the 

 flowers of the two middle rows never open ; those of the four outer 

 rows behaving in the same way as the flowers in Wheat. 



" While the flowers in M. vulgare are all hermaphrodite, in H, 

 distichum (2-rowed Barley) only those of the two middle rows are so, 

 and remain closed and fertilise themselves. Among these, however, 

 a few exceptionally occur with slightly open flowers, thus affording 

 the chance of cross-fertilisation by the purely male flowers of the 

 four marginal rows." 



