60. Brachiaria (Trin.) Griseb. (signalgrass)
One species, Europe, Asia, Africa.
The present delimitation follows Webster (1987, 1988), who
redefined generic limits in Brachiaria and the closely related Urochloa
to exclude all but the type species (B. eruciformis) from the former
genus. Webster’s (1987, 1988) analyses indicated that some of the morphological
characters used traditionally to separate the two genera, such as orientation
of spikelets on the inflorescence branches, were unreliable. Instead, he used a
number of minor spikelet characters to separate the two and, in the process,
transferred nearly all of the species traditionally treated in Brachiaria
to Urochloa. To further complicate the problem, the typification of Brachiaria
is poorly understood, and Veldkamp (1996) has submitted a proposal to conserve B.
eruciformis as the type of the genus in an effort to stabilize application
of the generic name. In general, however, the two groups are uncomfortably
similar in overall morphological variation, and may be reclassified as a single
genus at some point in the future (Clayton and Renvoize, 1986). If so, Urochloa
is the older of the two names and has priority.