This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol3", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
Rudbeckia fulgida Ait. Hort. Kew. 3: 251. 1789. R. spathulata Michx. Fl. Bor. Am. 2: 144. 1803. Rudbeckia missouriensis Engelm.; Boynton & Beadle, Biltmore Bot. Studies 1:17. 1901. R. palustris Eggert; Boynton & Beadle, loc. cit. 16. 1901.
Perennial; stem hirsute, or strigose-pubescent, slender, sparingly branched or simple, 1 -30 high. Leaves entire or sparingly serrate with distant teeth, more or less hirsute or pubescent on both sides, the basal and lower ones oblong or spatulate, obtuse, 2-4' long, 3-nerved, narrowed into margined petioles, the upper lanceolate, oblong-lanceolate, ovate or obovate, sessile, or slightly clasping at the base; heads few, 1'-1 1/2' broad; bracts of the involucre oblong or lanceolate, 3"-8" long; rays 8-15, linear, bright yellow or with an orange base; disk globose or globose-ovoid, brown-purple, 5"-7" broad; chaff of the receptacle linear-oblong, glabrous, or ciliate at the summit; pappus a minute crown.
In dry soil, New Jersey and Pennsylvania to Florida, west to Missouri and Texas. Consists of races differing in pubescence and leaf-form. Aug.-Oct.
Rudbeckia umbrosa Boynton & Beadle, Biltmore Bot. Studies 1:16. 1901.
Pubescent, perennial; stems l1/3°-3 1/2° tall, striate, simple or branched. Leaves thin, the basal and lower cauline ones ovate, 2'-4 1/2' long, coarsely serrate, rounded, truncate or cordate at the base, acute at the apex, the upper stem leaves diminishing in size, short-petioled or subsessile, narrower and less toothed than the lower; heads mostly several, showy; rays 8-12, yellow or orange-yellow, 7'-10" long; bracts of the involucre oblong to linear-oblong, 5"-7 1/2" long, pointed; disk somewhat depressed, 5' -7 1/2" wide, dark purple; chaff broad, densely ciliate at the apex; pappus coroniform.
In moist soil and woodlands, Kentucky, Tennessee and northwestern Georgia. Aug.-Sept.
Rudbeckia aspera Pers. Syn. 2: 477. 1807?
R. speciosa Wendler. Ind. Sem. Hort. Marb. 1828.
Perennial, more or less hirsute or hispid; stem branched above, 1°-4° high. Leaves firm, slender-petioled, 2'-5' long, 1'-2' wide, dentate with low teeth, acute or sometimes acuminate, 3-5-nerved; stem leaves sessile or partly clasping, or narrowed into broad margined petioles, laciniate or serrate, lanceolate to ovate, acuminate, often 6' long, the uppermost smaller and sometimes entire; heads several, 2'-3 broad; bracts of the involucre linear-lanceolate, acute; rays 12-20, 1'-11/2' long, bright yellow, usually orange at the base; disk depressed-globose, s"-8" broad, brown-purple; chaff of the receptacle obtusish or acute, ciliate or naked; pappus a short crown.
In moist soil, New Jersey to Michigan, south to Alabama and Arkansas. Aug.-Oct.