DISTINCTIONS IN CULTIVATED BARLEYS. 23 
FERTILITY. 
The variation in fertility is the most evident and the most vital of 
all the modifications that occur in barley. At each node of the 
rachis a group of three single-flowered spikelets is produced. In 
the 6-rowed barleys, each of these develops a separate kernel. As 
the groups of spikelets are placed alternately on opposite sides of 
the rachis the result is six columns of kernels from the base to the 
tip of the spike. In the 2-rowed barleys, only the central spikelet 
at each node is fertile, and therefore there are but two columns of 
grains. This reduction does not take place by the elimination of 
the outer spikelets but by their sterility. The median floret of each 
set of three accomplishes its normal development, while on either 
side are the small, undeveloped, infertile florets. However, the 
sexual organs have not disappeared. The three stamens reach an 
appreciable size and the ovary, though rudimentary in some ways, 
persists even to the plumose stigma. In one group of the 2-rowed 
barleys there is a still further modification of the lateral florets. In 
Abyssinian barleys there is a considerable number of forms in which 
the lateral spikelets are rudimentary ; that is, they no longer contain 
even infertile flowers, the whole spikelet being reduced to structures 
that are little more than hairlike. 
In the experience of the writer these well-known taxonomic divi- 
sions have proved entirely stable. The observations have included 
hundreds of varieties, and these varieties have been grown under 
such varying conditions as to stimulate monstrous developments in 
many structures^ but in no case has there been indication of bridging 
over these separations. It is the opinion of the writer that the numer- 
ous instances of exceptions recorded have been misinterpreted. The 
one cited by Kornicke (15) was most probably a cross, as the varia- 
tion of the progeny was such as is always secured by hybridization. 
The more common exceptions usually described are the occurrence of 
3-rowed and 8-rowed freaks, and 2-rowed barleys in which some of 
the lateral florets are fertile. All three exceptions are probably due 
to the formation of adventitious spikelets. Such spikelets are com- 
mon, and if several of them occur along one side of the rachis of a 2- 
rowed barley the result is a 3-rowed spike. If a duplication of the 
groups of spikelets at the nodes of one side of the rachis occurs in a 
6-rowed barley, the result is nine rows, which, if imperfect in any 
way, are easily mistaken for eight. It is entirely possible that florets 
of lateral spikelets of 2-rowed varieties are sometimes fertile, but in 
practically all of the numerous cases that have been noted by the 
writer a close inspection of such grains has shown them to be adven- 
titious, with the sterile floret also present. 
