470 
SYNGENESIA NECESSARIA. 
Mich. 2. p. 146. Sp. pi. 3. p. 2332. Pursh, 2. p. 573* Nutt. 2. p. 
L83. 
S. Tomentosum, Pursh, 2. p. 579. 
Stem two to three feet high, erect and procumbent, terete, covered like the 
underside of the leaves with a white tomentum. Leaves oblong, acute, irre- 
gularly toothed, conspicuously veined, the upper surface green, pubescent, 
the uppermost simply ovate. Flowers few, in an irregular corymb. Scales 
of the involucrum eight to ten, ovate, tomentose, imbricate. Florets of the 
ray eight to ten, rarely exceeding an inch in length, pubescent on the outer 
surface; of the disk numerous, dark purple. Seed obovate, crowned when 
young with two deciduous setaceous awns. 
Grows in the high dry pine barrens in the middle country. 
Flowers July — August. 
16. Elatum. Pursh. 
Leaves alternate, 
petiolate, cordate, sin- 
uate; scales of the in- 
volucrum obtuse. 
Pursh, 2. p. 579. 
Grows in Carolina. Pursh. 
S. foliis alternis, pe- 
tiolatis, cordatis, sinu- 
atis; involucri squamis 
obtusis. 
17. Reticulatum. Pursh. 
S. foliis alternis, 
ovato-lanceolatis, cor- 
datis, serratis, obtusi- 
usculis, viilosiusculis. 
Leaves alternate, 
ovate-lanceolate, cor- 
date, serrate, rather 
obtuse, slightly villous. 
Pursh, 2. p. 579. 
These two species with which I am unacquainted, and which are Very 
imperfectly distinguished, were described by Pursh from specimens in the 
Herbarium of Sir Joseph Banks. They were probably collected by Bartram 
(to whom the Botanists of the last century were indebted for a knowledge 
of many of our plants) on the confines of Georgia, Florida, and Alabama, 
the country of the Helianthus, the Silphium, the Rudbeckia, and perhaps I 
may add of the Solidago. 
