Transformation of jEgilops into TVJicnf. 113 



terminate at the middle of the base of each of the awns, are 

 ahnost equal to each other ; so that each valve may be divided 

 lons^itudinally into two halves nearly symmetrical. In JEgilops 

 triticoides, on the contrary, not only are the valves of the glume 

 larger, but one of the lateral nerves — the last but one — acquires 

 greater development than the others, and forms then a keel, 

 strongly marked above, dividing the valve into two unsymmetrical 

 parts. This keel is certainly less projecting than in the true 

 species of Triticum, but it is very clearly visible ; and it Is not 

 observed in j^gilojjs ovata. The awns of the glume are three or 

 four in number on each valve of jEgilops ovata, and moreover 

 they spread outwards ; habitually only two exist in JEgilops 

 triticoides, and these are constantly erect. It is true that between 

 the two awns of this latter plant Ave ordinarily see a tooth which 

 represents an abortive awn, but this is not constant ; and some- 

 times this tooth Is wanting altogether in the lower spikelets of 

 JEgilops triticoides, which separates it still farther from jEgilops 

 ovata : we shall recur to this fact. Now these distinctive cha- 

 racters are much more decided than those which separate ^^gilops 

 triticoides from JEgilops speltaformis. This is so evident that 

 M. Jordan himself, in his memoir on the Origin of Varieties and 

 Species of Fruit-trees, considers jEgilops triticoides as a species 

 quite distinct from j3^gilops ovata ; and he confounds JEgilops 

 triticoides Avith ^gilops speltaformis, as is proved by the follow- 

 ing passage, which I quote from that work: — "Thus, therefore, 

 the plant of which M. Fabre sowed the seeds is exactly JEgilops 

 i7'iticoides of Requien: he is right In this point; but that which he 

 obtained from their seeds, and cultivated for twelve years, is still 

 exactly the same ^gilops, and he is deceived when he believes 

 that he sees something different, or even a notable change of 

 characters. We have attentively compared cultivated and wild 

 specimens of his plant, .... and it has presented only unim- 

 portant differences, insufficient even to constitute a variety, and 

 analogous to those presented by every plant, when we compared 

 specimens grown in a good soil with those which have been 

 taken from a sterile field. M. Fabre is equally deceived when 

 he believes that his wild JEgilops triticoides has been derived 

 from u^Egilops ovata ; there is no reason why we should suppose 

 that xEgilops ovata has produced jEgilops triticoides rather than 

 the latter has produced ovata. Both hypotheses are absurd, 

 doubtless, but one is not less defensible than the other." M. 

 Jordan expressed himself thus in 1853. The plant cultivated by 

 M. Fabre, whicli three years ago M. Jordan did not regard even 

 as a simple variety, is now a legitimate species ; it is jEgilops 

 speltceformis. This form had been well distinguished by M. 

 Fabre at the time when M. Jordan completely Ignored it ; but if 

 VOL. XIX. I 



