Taxonomic history:
   1753: Linnaeus described this species as Panicum virgatum in Species Plantarum, 1st ed., p. 59.
   today: The current name for this species is Panicum virgatum L.

original Latin diagnosis
Panicum panicula virgata, glumis acuminatis laevibus extima dehiscente.

English translation
Panicum with a panicle twiggy; [and] with glumes acuminate [and] smooth, the outer dehiscing.

English translation with commentary

Panicum	Panicum
with a panicle	panicula - ablative singular of first declension feminine noun panicula, -ae
twiggy;	virgata - ablative singular feminine of group A adjective virgatus, -a, -um; modifies panicula
[and]	[added for smoother reading]
with glumes	glumis - ablative plural of first declension feminine noun gluma, -ae
acuminate	acuminatis - ablative plural feminine of group A adjective acuminatus, -a, -um; modifies glumis
[and]	[added for smoother reading]
smooth,	laevibus - ablative plural feminine of group B adjective laevis, laevis, laeve; modifies glumis
[and]	[added for smoother reading]
with the outer [one]	extima - ablative singular feminine of group A adjective extimus, -a, -um; modifies one of the glumis
dehiscing.	dehiscente - ablative singular feminine of the present active participle of third conjugation verb dehisco, -ere, -ivi, —; modifies extima