63a. Some of the involucral bracts leaf-like, longer than the heads (3-20 dm. high; flowers yellow or greenish, summer and autumn) (Beggar Ticks) --126.

63b. Bracts short and not leaf-like --64.

64a. Heads 7-20 mm. wide, in a flat-topped or convex cl.u.s.ter (3-10 dm. high; flowers yellow, summer) (Tansy) --65.

64b. Heads smaller, in spikes, racemes, or panicles (flowers yellow or greenish, late summer and autumn) (Wormwood) --66.

65a. Heads 7-10 mm. wide, numerous in a dense cl.u.s.ter =Tansy, Tanacetum vulgare.=

65b. Heads 10-20 mm. wide, few, 2-10 in a loose open cl.u.s.ter =Tansy, Tanacetum huronense.=

66a. Heads 2-3 mm. broad (4-15 dm. high) --67.

66b. Heads 4-6 mm. broad (3-10 dm. high) --69.

67a. Leaf-lobes narrowly linear, strictly entire =Wormwood, Artemisia caudata.=

67b. Leaf-lobes serrate --68.

68a. Heads in a loose spreading panicle =Wormwood, Artemisia annua.=

68b. Heads in axillary cl.u.s.ters, producing a leafy spike-like panicle =Wormwood, Artemisia biennis.=

69a. Leaf-lobes narrowly linear --70.

69b. Leaf-lobes oblong to obovate, not linear --71.

70a. Shrubby; involucre p.u.b.escent =Southernwood, Artemisia abrotanum.=

70b. Herbaceous; involucre glabrous or rarely p.u.b.escent =Wormwood, Artemisia canadensis.=

71a. Leaves finely gray-p.u.b.escent on both sides =Wormwood, Artemisia absinthium.=

71b. Leaves smooth or nearly so above, densely white-woolly beneath =Mugwort, Artemisia vulgaris.=

72a. Heads 2-4 cm. broad, purple, blue, or rarely white (3-6 dm.

high; summer) --92.

72b. Heads 1 cm. wide or less --73.

73a. Leaves densely white-woolly beneath (flowers yellowish, late summer) --74.

73b. Leaves smooth or hairy, never white-woolly --75.

74a. Heads 6-8 mm. wide (4-8 dm. high) =Wormwood, Artemisia stelleriana.=

74b. Heads 3-4 mm. wide (5-10 dm. high) =Wormwood, Artemisia ludoviciana.=

75a. Princ.i.p.al bracts of the involucre 5, with frequently a few much smaller ones --76.

75b. Princ.i.p.al bracts of the involucre numerous --77.

76a. Heads few in small terminal cl.u.s.ters; foliage somewhat viscid-p.u.b.escent (6-15 dm. high; flowers yellow, summer) --114a.

76b. Heads very numerous in flat-topped cl.u.s.ters; foliage never viscid-p.u.b.escent (1-2 m. high; flowers white, late summer) --105c.

77a. Leaves broadly halberd-shape, 3-lobed (1-2 m. high; flowers white, late summer) --105b.

77b. Leaves lobed only at the base (5-10 dm. high; flowers yellow, summer) --93a.

77c. Leaves pinnatifid (2-8 dm. high; flowers yellow) --172.

78a. Bracts of the involucre dry and chaffy, at least at the tip; plants always p.u.b.escent and usually white-woolly --79.

78b. Bracts of the involucre green or colored, but never dry and chaffy --90.

79a. Pappus none; heads 3-4 mm. wide, in ample panicled spikes (flowers yellowish, late summer) --74b.

79b. Pappus a minute ring or crown; leaves crenate (5-10 dm. high; flowers yellow, summer) --93a.

79c. Pappus of hairs; heads in flat-topped cl.u.s.ters or slender spikes --80.

80a. Heads sessile or subsessile in small flat-topped cl.u.s.ters; flowering in spring or early summer; princ.i.p.al leaves basal (1-4 dm. high; flowers white or purplish) (Everlasting) --81.

80b. Heads in terminal spikes (2-6 dm. high; flowers purplish, summer) =Cudweed, Gnaphalium purpureum.=

80c. Heads in small or large flat-topped cl.u.s.ters, flowering in summer or autumn; princ.i.p.al leaves on the stem --88.

81a. Stolons from the basal rosette of leaves leafy throughout and ascending at the tip --82.

81b. Stolons prostrate throughout, leafy only at the tip --87.

82a. Basal leaves 2-5 cm. long, 1-nerved --83.

82b. Basal leaves 5-12 cm. long, 3-nerved --84.

83a. Basal leaves spatulate or oblanceolate, smooth above =Everlasting, Antennaria canadensis.=

83b. Basal leaves obovate, p.u.b.escent above =Everlasting, Antennaria neodioica.=

84a. Basal leaves smooth above =Everlasting, Antennaria parlinii.=

84b. Basal leaves dull green and p.u.b.escent above --85.

85a. Heads 6-8 mm. high =Everlasting, Antennaria plantaginifolia.=

85b. Heads 8-11 mm. high --86.

86a. Leaf-blade ovate or obovate =Everlasting, Antennaria fallax.=