CARDUACEAE 1301 
2. Mesadenia similis Small. Similar to M. atriplicifolia in habit. Stem relatively 
stout, furrowed, corymbosely branched above : leaf-blades green above, glaucous beneath, 
those of the basal and lower stem-leaves much larger than those of the upper, undulate- 
sinuate, deeply cordate, long-petioled: heads rather smaller than those of M. atriplicifolia. 
On prairies and in low grounds, Arkansas. Summer. 
3. Mesadenia atriplicifolia (L.) Raf. Stems 1-2 m. tall, glabrous, terete: leaf- 
blades various, those of the basal leaves orbicular-reniform or broadly ovate, 10-15 em. 
broad, those of the stem-leaves smaller, ovate or triangular, or narrower above, all angu- 
lately 3-7-lobed or coarsely and sharply toothed, cordate to cuneate at the base, all glaucous 
beneath : heads numerous: involucral bracts linear, oblong-linear, oblong-lanceolate, 8-11 
mm. long, wingless: achenes 4-4.5 mm. long. 
In open woods and thickets, Ontario to Minnesota, Florida and Kansas. Summer and fall. 
4. Mesadenia máxima Harper. Stem about 1.5 m. tall, terete, glaucous: leaf- 
blades thickish, those of the lower leaves about 25 cm. long and 20 em. broad, truncate at 
the base, long-petioled, those of the upper gradually reduced in size and proportionately 
narrower, all glaucous on both sides, very coarsely sinuate-toothed, more or less digitately 
veined, the veins forking and often anastomosing : heads in a terminal compound corymb 
5-6 dm. long and nearly as broad : involucral bracts bright green, about 1 cm. long, wing- 
less. 
In dry pine lands, Sumter County, Georgia. Summer. 
5. Mesadenia ovata (Walt.) Raf. Stems 8-12 dm. tall, terete: leaf-blades thin- 
nish, ovate to oval, 8-20 cm. long, entire or repand-undulate, truncate and cuneate and 
palmately nerved at the base; petioles of the basal and lower stem-leaves as long as the 
blades : heads often numerous: involucral bracts narrowly oblong or linear-lanceolate, 8-10 
mm. long: corollas with very little throat. 
In damp woods or swamps, Georgia and Florida to Louisiana. 
6. Mesadenia lanceolata (Nutt.) Raf. Stems 8-15 dm. tall, terete: leaf-blades 
linear, narrowly lanceolate or linear-oblong, 5-30 em. long, entire or repand-denticulate ; 
petioles margined, the lower ones longer than the blades: heads relatively few : involucral 
bracts linear or narrowly oblong-lanceolate, 8-10 mm. long : achenes about 5 mm. long. 
In wet pine lands, Georgia and Florida to Louisiana. Spring to fall. 
7. Mesadenia diversifdlia (T. & G.) Greene. Similar to M. atriplicifolia in habit, 
but not glaucous : corolla-lobes but little longer than the throat. Little known. 
In swamps, South Carolina to Florida. Summer. 
8. Mesadenia diffórmis Small. Stems 7-11 dm. tall, terete: leaf-blades various, 
those of the lower cauline leaves ovate, some of them narrowly ovate, undulate or merely 
sinuate, 2-4.5 cm. long, obtuse, on greatly elongated petioles, those of the upper cauline 
leaves ovate in outline but hastate and sharply dentate or dentate-lobed, 2.5-4 cm. long, even 
the uppermost one like the others nearly truncately narrowed into petiole-like bases: heads 
few in the terminal corymb : involucral bracts winged. 
In swamps, western Florida. Summer. 
9. Mesadeniatuberdsa (Nutt.) Britton. Stems 6-12 dm. tall, sulcate or angled: leaf- 
blades thickish, ovate, oval, oblong-lanceolate or narrowly elliptic, 5-20 em. long, 5-9- 
nerved, entire, denticulate or repand-dentate, attenuate or truncate at the base; petioles 
margined, those of the basal and lower stem-leaves as long as the blades or much longer : 
involucral bracts narrowly oblong, winged, 8-10 mm. long: achenes 4.5-5 mm. long, 
granular, ribbed. 
‘On damp prairies, Ontario to Minnesota, Alabama and Louisiana. Summer. 
10. Mesadenia Floridàna (A. Gray) Greene. Stems 7-12 dm. tall, channeled: leaf- 
blades thickish, ovate, oval or oblong, 5-15 cm. long, coarsely crenate or crenate-dentate, 
cuneately constricted at the base, the upper ones sessile or nearly so: heads numerous: invo- 
lucral bracts oblong or nearly so, 10-12 mm. long, winged : corollas with lobes slightly longer 
than the throat: achenes about 5 mm. long. 
In low pine lands, Florida. Spring and summer. 
11. Mesadenia sulcata (Fernald) Small. Stem 1-1.5 m. tall, deeply channeled : 
leaf-blades ovate to oblong-ovate, narrowly elliptic or oblong-lanceolate, 8-20 cm. long, or 
shorter toward the inflorescence, those of the basal and lower cauline leaves sinuate-dentate, 
narrowed into long petioles, the upper closely sessile, usually sharply and deeply toothed : 
heads numerous : involucral bracts oblong or oblong-lanceolate, 8-10 mm. long, winged. 
In sandy bogs or wet woods, southern Georgia and northern Florida. Summer and fall. 
