526 ANGIOSPERMAEMONOCOTYLEDONES 



these species as homogamous, and says that they open their flowers hke A. sativa in 

 favourable weather, and are pseudo-cleistogamous when it is unfavourable. 



3028. A. sterilis L. This species is homogamous. 



looi. Trisetum Pers. 



3029. T. pratense Pers. (= T. flavescens Beauv.). Kerner states that the 

 anthers of this species dehisce about 7-8 a.m., and Warnstorf thinks this takes 

 place 6-7 a.m. The pollen-grains are pyramidal, about 37 /u. long and 25-8 fi. 

 broad. The flowers are homogamous. 



1002. Eleusine Gaertn. 



3030. E. coracana Gaertn. Kornicke (op. cit.) says that the flowers of this 

 species open. The tips of the stigmas reach those of the glumes. The longitudinallj 

 dehiscing anthers are situated on the same level as the stigmas, and as both mature 

 simultaneously, are directed upwards, and are more or less apposed, self-poUinatior 

 takes place, though crossing is not excluded. 



1003. Poa L. 



3031. P. abyssinica Jacq. (= Eragrostis abessinica Z.). (Kornicke, op. cit. 

 In this species fertilization usually takes place pseudo-cleistogamously, as th( 

 anthers hang against the stigmas, and, at least in the forms observed by Kornicke 

 the flowers do not open. 



3032. P. pratensis L. Kirchner ('Flora v. Stuttgart,' p. 141) describes thi 

 species as homogamous with persistent stigmas, which depend laterally out of th( 

 flower when the blue-grey anthers are emptied. Kerner says that species of thi 

 genus dehisce between 4 and 5 a.m. Beijerinck states that they are self-fertile. 



3033. P. nemoralis L. This species is homogamous, and the anthers dehisc 

 towards midday. The pollen-grains are up to 37 /^ in diameter (Warnstorf, Verh 

 bot. Ver., Berlin, xxxviii, 1896). 



3034. P. annua L. 



Visitors. Herm. Miiller observed the hover-fly Melanostoma mellina L. 



1004. Briza L. 



3035. B. media L. Hildebrand (' Bestaubungsverh. d. Gramineen,' p. 75J 

 describes this species as homogamous. The anthers dehisce for the first time earl 

 in the morning, and for the second time between 6 and 7 p.m. The pollen-grair 

 are pyramidal in form, about 40 fx long and 31 /i, broad (Warnstorf, Verh. bot. Ver 

 Berlin, xxxviii, 1896). 



1005. Glyceria R. Br. 



3036. G. fiuitans R. Br. (= G. plicata Fries). Kirchner (' Beitrage/ p. < 

 says that this species is protogynous with persistent stigmas. The two white, brusl 

 like stigmas are mature when the glumes diverge. After the filaments have the 

 elongated, the stamens bend over, and the bright-yellow anthers dehisce. Aft 



11 



