Nettle - (Easton's Bible Dictionary)
(1.) Heb. haral, "pricking" or "burning," Prov. 24:30, 31 (R.V. marg., "wild vetches"); Job 30:7; Zeph. 2:9. Many have supposed that some thorny or prickly plant is intended by this word, such as the bramble, the thistle, the wild plum, the cactus or prickly pear, etc. It may probably be a species of mustard, the Sinapis arvensis, which is a pernicious weed abounding in corn-fields. Tristram thinks that this word "designates the prickly acanthus (Acanthus spinosus), a very common and troublesome weed in the plains of Palestine."
(2.) Heb. qimmosh, Isa. 34:13; Hos. 9:6; Prov. 24:31 (in both versions, "thorns"). This word has been regarded as denoting thorns, thistles, wild camomile; but probably it is correctly rendered "nettle," the Urtica pilulifera, "a tall and vigorous plant, often 6 feet high, the sting of which is much more severe and irritating than that of our common nettle."