116 A TEXT-BOOK OF GRASSES 
latter, however, the inflorescence is really branched, 
shortened branchlets with 2 spikelets being borne in each 
of the cavities of the axis. Sometimes, as in Tripsacum 
and Euchlena (Fig. 11), the axis disarticulates and the 
1-seeded joints become hard bead-like fruits. The cob of 
an ear of corn is a greatly thickened axis of inflorescence, 
the structure of which is discussed in Par. 202. 
The spikes and spike-like racemes of Chloridez and of 
many Panicee are I-sided. Here the axis has developed 
so unsymmetrically that the 2 rows of spikelets have been 
forced to one side. The axis may appear thin and much 
flattened as in many species of Paspalum (e. g., P. repens 
and P. stellatum) or somewhat triangular with a row of 
spikelets on each of 2 sides, as in crab-grass. 
The name rachis is usually applied to the axis of spikes, 
and spike-like racemes or panicles, or to the axis of any 
contracted inflorescence or portion of an inflorescence. 
147. Branching of panicles—The main branches of a 
panicle are known as the primary branches. Those which 
arise from these are secondary branches and this name 
may be applied to branches of the third or higher order. 
The ultimate branches or branchlets which are the stalks 
of the individual spikelets are the pedicels and will be 
considered when the structure of the spikelet is discussed. — 
The primary branches of a panicle often appear to be 
verticillate or at least more than one from a node. It 
will be observed however that in many cases there is 1 
primary branch and that the others are secondary branches 
developed at the base of a primary branch. If the verticils 
are composed of primary branches the aggregation is 
due to the failure of the internodes to elongate. 
If the several branches originating at one node all stand at 
one side of the main axis and those at the next node stand on the 
