12 BULLETIN" 622, U. S. DEPARTMENT OF AGRICULTURE. 



Table II.— Scheme of classification of barley founded upon fertility, eliminating density. 



Genus. 



Section. 



Subsection. 



Species. 



Hordeum 





(Eu. vulgare 



vulgare. 









(distichon. 







Ideflciens. 



KEY TO THE SPECIES. 



The meaning of the graphic representation is made somewhat 

 clearer by consulting the key to the species. It will be noted that the 

 absence of appendages on the lateral florets is used to separate the 

 species intermedium. This distinction is in reality one of fertility, 

 the most obvious indication of which is the absence of appendages on 

 the lemma. These lateral florets are probably not comparable to the 

 lateral florets of vulgare but to the lateral florets of distichon, differ- 

 ing from the latter in having become fertile. 



Key to the species. 



All spikelets fertile (6-rowed barley). 



Lemmas of all florets awned or hooded vulgare L. 



Lemmas of lateral florets bearing neither awns nor hoods. 

 <-> intermedium Kcke. 



Only the central spikelets fertile (2-rowed barley). 



Lateral spikelets consisting of outer glumes, lemma, palet, rachilla, and 



usually rudiments of the sexual organs distichonli. 



Lateral spikelets reduced, usually to only the outer glumes and rachilla, 

 rarely more than one flowering glume present, and never rudiments of 

 sexual organs deficiens Steud. 



Of these species the first three present no nomenclatural difficul- 

 ties. Vulgare and distichon trace direct to Linnaeus (1753), and in- 

 termedium to Kornicke (1882, p. 125). In the fourth there is more 

 question of priority. According to Kornicke and Werner (1885), 

 Steudel described deficient in 1842. Apparently there was no pub- 

 lished description, the identification being only the name written on 

 a herbarium sheet of Schimpers Abyssinian collection. The name 

 first applied appears to have been decipiens and not deficiens. In 

 1854 (p. 351) Steudel gives a very complete description of deficiens 

 as a species. So far as the writer can learn, this is the first time the 

 name was used in print. In May, 1842, Seringe (p. 194) in addi- 

 tions to the genus Hordeum describes all the common forms of defi- 

 cient barley under the variety abyssinicum, 



In the key the only, question arises in the separation of the defi- 

 cient 2-rowed from the normal 2-rowed barleys. Deficient types are 



