Ontario Weeds: Giant foxtail
Table of Contents
Name: Giant foxtail, Setaria faberii
Giant foxtail (A - upper part of plant; B - comparison of giant foxtail head, left, with green foxtail head, right).
Giant foxtail. G. Young plant showing finely hairy leaf
surfaces. H. Leaf-base showing dense covering of very short hairs
on upper surface of leaf-base, hairy ligule with longer hairs
at margins of collar, and short hairs along edge of leaf sheath.
Stem and leaf-base characteristics of a typical grass.
Stems & Roots: Stems up to 2m
(6.5ft) high, smooth; leaf sheaths mostly smooth, except hairy along
the margins; leaf blades 30-55cm (12-21.5in.) long, 3-17mm ( 1/8-2/3in.)
wide, usually finely hairy throughout the entire upper surface of
all leaves and occasionally also on the undersurface (seen by rolling
the leaf over a finger and viewing it against the light); ligule
a dense band of hairs, about 1.0mm (1/25in.) long; no auricles;
Similar Species: It is distinguished from Green foxtail by its usually larger, nodding inflorescence, its distinctly cross-wrinkled grains and usually hairy upper surface of leaves, and from Yellow foxtail by its larger, greenish-yellow rather than orange-yellow inflorescence, and by the upper surfaces of its leaf blades being finely short-hairy throughout their length rather than bearing a few long, kinky hairs near the stem. The technical character that distinguishes Giant foxtail from Green foxtail is that its second or upper glume covers only about ¾ of the fertile floret, whereas in Green foxtail it covers nearly the entire floret.
For more information:
Toll Free: 1-877-424-1300