332 CLEISTOGAMIC FLOWERS. CHAP. VIII. 



Hordeum it has been shown by Delpino * that the ma- 

 jority of the flowers are cleistogamic, some of the others 

 expanding and apparently allowing of cross-fertilisa- 

 tion. I hear from Fritz Miiller that there is a grass 

 in Southern Brazil, in which the sheath of the upper- 

 most leaf, half a metre in length, envelopes the whole 

 panicle; and this sheath never opens until the self- 

 fertilised seeds are ripe. On the roadside some plants 

 had been cut down, whilst the cleistogamic panicles 

 were developing, and these plants afterwards produced 

 free or unenclosed panicles of small size, bearing per- 

 fect flowers. 



Leersia oryzoides. It has long been known that 

 this plant produces cleistogamic flowers, but these were 

 first described with care by M. Duval-Jouve.f I pro- 

 cured plants from a stream near Eeigate, and cultivated 

 them for several years in my green-house. The cleis- 

 togamic flowers are very small, and usually mature their 

 seeds within the sheaths of the leaves. These flowers 

 are said by Duval-Jouve to be filled by slightly viscid 

 fluid; but this was not the case with several that I 

 opened; but there was a thin film of fluid between the 

 coats of the glumes, and when these were pressed the 

 fluid moved about, giving a singularly deceptive ap- 

 pearance of the whole inside of the flower being thus 

 filled. The stigma is very small and the filaments ex- 

 tremely short; the anthers are less than -gV of an inch 

 in length, or about one-third of the length of those 

 in the perfect flowers. One of the three anthers de- 

 hisces before the two others. Can this have any rela- 

 tion with the fact that in some other species of Leersia 



* ' Bollettini del Comizio agrario Hordeum, in ' Monatebericht d. K. 



Parmense.' Marzo e Aprile, 1871. Akad. Berlin,' Oct. 1872, p. 7GO. 



An abstract of this valuable paper f 'Bull. Bot. Soc. de France,' 



is given in 'Bot. Zeitnng,' 1871. torn. x. 1863, p. 194. 

 p. 537. See also Hildebrand on 



