CHAP. VIII. LEERSIA. 333 



only two stamens are fully developed ? * The anthers 

 shed their pollen on the stigma; at least in one in- 

 stance this was clearly the case, and by tearing open 

 the anthers under water the grains were easily detached. 

 Towards the apex of the anthers the grains are arranged 

 in a single row and lower down in two or three rows, 

 so that they could be counted; and there were about 35 

 in each cell, or 70 in the whole anther; and this is an 

 astonishingly small number for an anemophilous plant. 

 The grains have very delicate coats, are spherical and 

 about in^nj- of an inch (.0181 mm.), whilst those of the 

 perfect flowers are about ^fa of an inch (.0254 mm.) 

 in diameter. 



M. Duval-Jouv.e states that the panicles very rarely 

 protrude from their sheaths, but that when this does 

 happen the flowers expand and exhibit well-developed 

 ovaries and stigmas, together with full-sized anthers 

 containing apparently sound pollen; nevertheless such 

 flowers are invariably quite sterile. Schreiber had pre- 

 viously observed that if a panicle is only half protruded, 

 this half is sterile, whilst the still included half is fer- 

 tile. Some plants which grew in a large tub of water 

 in my green-house behaved on one occasion in a very 

 different manner. They protruded two very large much- 

 branched panicles; but the florets never opened, though 

 these included fully developed stigmas and stamens 

 supported on long filaments with large anthers that 

 dehisced properly. If these florets had opened for a 

 short time unperecived by me and had then closed again, 

 the empty anthers would have been left dangling out- 

 side. Nevertheless they yielded on August 17th an 

 abundance of fine ripe seeds. Here then we have a near 

 approach to the single case as yet known f of this grass 



* Asa Gray, ' Manual of Bot. of t Dr. Ascherson, ' Bot. Zcitung,' 

 United States,' 1856, p. 540. 1884, p. 350. 



