24 Engelmann and Gray, 
169. Srinuineia sytvatica, Linn. Prairies. April—June. 
170. S. tieustrina, Michx. Thickets near water-courses, 
Houston. May.— 'The staminate flowers are rather conspicu- 
ously pedicillate, not brevissime pedicillatis, as described by 
Michaux. 
171. Prninopuyrum Linpuermert (n. sp.): annuus, stel- 
lato-tomentosus ; caule (4—5-pedali) erecto ramoso ; _foliis 
longe petiolatis e basi ovata subcordatave lanceolatis sepe 
acutato-mucronatis, inferioribus denticulatis ; floribus foemineis 
paucis ad basin spicee masculze ; staminibus sub-12 ; stigmati- 
bus plerumque 12; seminibus vix compressis. — Dry prairies, 
Houston to the Brazos. Also, Texas, Drummond, and West- 
ern Louisiana, Leavenworth. A taller, more upright plant 
than P. capitatum (Croton, Michz.,) with larger and less 
canescent leaves; the lower 4—5 inches long, and gradually 
acuminate to an usually sharp point, on petioles 3 inches long. 
The spike in fruit is less capitate, and the seeds are smaller 
and less compressed. Something like intermediate specimens 
between this and the P. capitatum, which also grows in 
A remaining species, the Polygonum fimbriatum of Elliott, which has been deemed 
a near ally of Polygonum polygamum, may be taken as the type of a new genus, 
viz.: 
THYSANELLA, A. Gr. 
Flores dioico-polygami. Perigonium pentaphyllum petaloideum ; phyllis omnibus 
erectis margine scariosis et eroso-fimbriatis, duobus exterioribus cordato-sagittatis 
post anthesin auctis, interioribus minoribus ovato-lanceolatis pectinato-fimbriatis. 
Stamina 8: filamenta filiformia perigonium adequantia. Ovarium (infertile) trigo- 
num: styli 3, filiformes; stigmatibus simplicibus. Fructus ...... Semen 
Ete dade Caeat® with <ais — Herba ramosa, glabra, (bipedalis,) in arenosis Geor- 
gie vigens, caulibus virgatis strictis ; foliis angusto-linearibus elongatis acutatis 
striatulis sessilibus; ochreis truncatis setis capillaribus longissime barbatis; floribus 
(incarnatis) racemoso-spicatis ; spicis solitariis vel geminis, paniculatis, dense 
imbricatim ochreato-bracteatis ; ochreis oblique truncatis in acumen aristiforme 
productis ; pedicellis in medio articulatis. 
T. Fimpriata. = Polygonum fimbriatum, Ell. Sk. I. p. 588. 
Elliott seems to have described from specimens with hermaphrodite flowers ; but 
in mine (which were collected by Dr. Leavenworth either in Georgia or Florida) the 
ovaries are apparently all sterile. The fruit and seed is, therefore, unknown to me, 
and I am not certain that the outer sepals increase in size after flowering. 
A. Gr. 
