Rudbeckia Compositae 965 



Summit of chaff (except the outer rows) more or less ciliate on the margins or 

 pubescent within. 

 Chaff more or less pubescent within and usually more or less pubescent with- 

 out; involucral bracts hispid above; corollas about 4 mm long, the lobes 

 about 1 mm long; achenes about 2 mm long; plants mostly on the crests of 

 wooded ridges; blades of stolons narrow, lanceolate or elliptic-lanceolate, 

 generally less than 3 cm wide or in a wet season under cultivation some- 

 what ovate and up to 5 cm wide 5. R. fulgida. 



Chaff not pubescent within, rarely with a few hairs, and glabrous without; in- 

 volucral bracts glabrous above; plants of moist places. 

 Largest leaves of stolons mostly 3-8 cm wide, of an ovate or oval type, 

 their petioles mostly 7-17 cm long; median and upper cauline leaves 

 sessile or on short, margined petioles; achenes 3 mm long. 

 Ligules of rays 1.5-2 cm long; disk usually less than 14 mm wide; chaff 



mostly with narrow-triangular tips 6. R. umbrosa. 



Ligules of rays 2-4 cm long; disk 12-18 mm wide; chaff mostly with wide- 

 triangular tips 1. R. Sullivantii. 



Largest leaves of stolons less than 3 cm wide, lanceolate, or elliptic-lanceo- 

 late, narrowed to a very long cuneate base, remotely shallow-crenate, 

 their petioles mostly 2-12 cm long; median and upper cauline leaves 

 usually narrowed to long, margined petioles; achenes 2-2.5 mm long. 



8. R. palustris. 



Summit of chaff with erose or denticulate margins, sometimes one or more of 

 the outer ones with a few ciliate hairs. 

 Stems more or less densely retrorsely hirsute, appressed-pubescent above; in- 

 volucral bracts hispid above; ligules of rays less than 25 mm long; leaves 

 of stolons ovate or oval, narrowed or rounded at the base. . .9. R. Deamii. 

 Stems glabrate, sparingly hispid, or rarely spreading or upwardly pubescent; 

 involucral bracts glabrous above; ligules of rays 20-40 mm long, usually 

 more than 25 mm long; leaves of stolons large, of an ovate type, cordate 

 or subcordate at the base 7. R. Sullivantii. 



1. Rudbeckia hirta L. Black-eyed Susan. Map 2112. This species 

 I am regarding as a species complex. The plants in our area are variable. 

 Some are annual and flower mostly in June and July ; these probably be- 

 long to the typical form. They are found in all parts of the state and are 

 more or less frequent in both the glaciated and unglaciated areas. They 

 are usually found in fallow fields, prairie habitats, and open black oak 

 woods and along roadsides and railroads. I have found them in acid 

 marshes and once in great numbers on the marl border of a lake. It is 

 to be noted that the border of the lake was more than 100 feet wide and 

 the plants covered about an acre. Those that grew in the moist part of 

 the border were simple, usually bearing but one head while those on the 

 beach margin where it was dry were branched and had many heads. 



These early flowering plants also vary in the size and shape of the 

 leaves and in the color of the rays. Miss Edna Banta found a specimen 

 in Jefferson County which I determined as Rudbeckia bicolor, overlooking 

 the fact that this species sometimes has flowers with the base of the rays 

 a maroon color. I am now referring her specimen to Rudbeckia hirta. 

 The bracts of this form are mostly 10-12 mm long, rarely one up to 20 

 mm long. The rays are mostly 20-35 mm long. The heads are on long 

 peduncles and well developed ones are 15-22 mm wide. 



