232 Engelmann and Gray, 



169. Stillingia sylvatica, Linn. Prairies. April — June. 



170. S. ligustrina, Michx. Thickets near water-courses, 

 Houston. May. — The staminate flowers are rather conspicu- 

 ously pedicillate, not brevissime pedicillatis, as described by 

 Michaux. 



171. PlLINOPHYTUM LlNDHEIMERI (fl. Sp.) I anilUUS, Stel- 



lato-tomentosus ; caule (4-5-pedali) erecto ramoso ; foliis 

 longe petiolatis e basi ovata subcordatave lanceolatis saspe 

 acutato-mucronatis, inferioribus denticulatis ; floribus foemineis 

 paucis ad basin spicae masculae ; staminibus sub- 12 ; stigmati- 

 bus plerumque 12; seminibus vix compressis. — Dry prairies, 

 Houston to the Brazos. Also, Texas, Drummond, and West- 

 ern Louisiana, Leavenwo?'th. A taller, more upright plant 

 than P. capitatum (Croton, Michx.,) 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 fimhriatum 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 llliformia perigonium adacquantia. Ovarium (infertile) trigo- 



num : styli 3, filiformes ; stigmatibus simplicibus. Fructus Semen 



— Herba ramosa, glabra, (bipedalis,) in arenosis Geor- 

 gia 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. fimbriata. = 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. Gb. 



