HYBRIDISATION AND WHEAT HYBRIDS 



of Gussone and Tenore recorded its occurrence in Sicily. It has since 

 been found in Algeria. 



Aegilops triticoides (Figs. 222, 223) is a rare sporadic plant, generally 

 quite sterile, with tall erect culms 50-90 cm. high, bearded or semi- 

 bearded, cylindrical ears 8-10 cm. long, consisting of 6-10 or more spikelets, 

 each possessing two flowers. The empty glumes are flatter than those of 

 other species of Aegilops and distinctly keeled, with only one or two awns 

 and rudiments of others. When ripe the ear disarticulates near its base 

 and falls to the ground (Fig. 223). 



Aegilops ovata is a common species 

 in all the countries bordering on the 

 Mediterranean. It has somewhat decum- 

 bent stems 20-30 cm. long and short ears 

 about 4 cm. long. The latter usually 

 possess two fertile spikelets, each contain- 

 ing a pair of grains when ripe, the base 

 and apex of the inflorescence being com- 

 posed of a few degenerate spikelets or 

 spikelets with staminate flowers only. 



The empty glumes which almost cover 

 the rest of the spikelet are ventricoae, 

 rounded on the back, without any distinct 

 keel, but possessing a number of prominent 

 nerves ; at the apex are 4 awns (Fig. 223). 



When the ear is ripe it disarticulates 

 below the first fertile spikelet, and after 

 falling to the ground becomes buried in 

 the soil, where its grains, tightly enclosed 

 in the glumes, germinate and give rise to 

 a tuft of three or four closely knitted but 

 independent plants. 



In 1838 Ksprit Fabre, a gardener living 

 at Agde, near Montpellier, observed that 

 although the grains of A. ovata usually 

 give rise to plants like the parent, in some rare instances plants of Aegilops 

 ovata and Aegilops triticoides are found growing from grains of the saint- 

 ear. The fact of two strikingly different plants springing from separate 

 grains of the same inflorescence attracted the attention of botanists, and 

 its bearing on the fixity of species was widely discussed. 



Fabre cultivated A. triticoides for about twenty years, at first in an 

 enclosed garden, and subsequently in open fields, and found that the 

 plants in successive seasons became more and more like Bread Wheat 

 (Tritictim vulgarc). 



FlG. 222. Ear of .-I r&'iY/>f tritiri,irs 

 nd empty ulumr (nat. M/I->. 



