212 UNITED STATES AND MEXICAN BOUNDARY. 
ZANNICHELLIA PALUSTRIS, Linn.; Kunth, Enum. З, p. 124; Torr.l. c. p. 253.  Slow-flowing 
streams and stagnant waters, western Texas, Chihuahua, and Sonora. 
POTAMOGETON PECTINATUS, Linn.; Torr. Fl. New York, 2, p. 247. Р. marinum, Linn.; Michz, 
Fl. 1, р. 102. Flowing water near San Diego, California; Parry. Tucson, Sonora; Schott. 
(No. 1895, Wright.) 
POTAMOGETON HYBRIDUS, Miche. Fl. 1, р. 101; Torr. l. c. In water on the prairies of the 
Guadalupe river, Texas, May; Wright. 
POTAMOGETON PAUCIFLORUS, Pursh, Fl. 1, p. 121; Torr. l.c. P. gramineus, Micha. Fl, p. 102, 
non Linn. Stagnant water of the Limpio, July ; Bigelow. 
PoTAMOGETON LUCENS, Linn.; Kunth, Enum. 8, p. 132; Torr. l. c. p, 255. San Antonio, 
Texas, to the Rio Grande. 
PoTAMOGETON NUTANS, Linn.; Kunth, Enum. 3, p. 127; Torr.l. c. p. 253. Waters of the 
Limpio, Texas; Bigelow. Ojo Caliente, Chihuahua ; Thurber. Los Noyales, Sonora; Capt. 
E. K. Smith. 
ALISMACEJE, by Dr. George Engelmann. 
SAGITTARIA SIMPLEX, Pursh, Fl. 2, p. 397; Gray, Man. ed. 2, p. 439. In ponds, western | 
Texas; Wright. қ 
SAGITTARIA CALYCINA (Engelm. MSS ): pedicellis fertilibus sterilia æquantibus; fructiferis re- 
curvatis ; floribus omnibus hermaphroditis, fertilibus subdodecandris, sterilibus polyandris ovaria 
pauca sterilia gerentibus ; -filamentis subulatis leviusculis seu tenuiter papillosis antheram late 
ovatam subzequantibus seu paullo superantibus ; stylo erecto ovario longiore in carpellis maturis 
obovatis duplo longioribus horizontali; sepalis orbiculatis carpellorum capitatum arcte involven- 
tibus. 
Var. a. MAxIMA : foliis maximis sinu latissimo hastatis, lobis divaricatissimis tenuiter subulato- 
appendiculatis ; scapo robusto ramoso ; bractedlis lanceolatis acutis; verticillis fructiferis plu- 
ribus capitulis magnis.—On the Red river, Louisiana ; Dr. Hale. 
Var. B. MEDIA: foliis minoribus sinu latissimo hastatis lobis divaricatis s. divaricatissimis - 
acuminatis; scapo debili simplici verticillo infimo solum (raro duobus) fructifero; bracteis ova- 
tis obtusis ; capitulis minoribus.—Saline swamps, Jefferson county, Missouri ; Engelmann. 
Var. y. FLUITANS : foliis oblongo-linearibus fluitantibus; scapo debili verticillis sepe 1—2-floris; 
bracteis obtusis ; pedicellis elongatis inequalibus; capitulis minoribus.— Ponds and slow-flowing 
waters, western Texas. Wright, No. 1899. Also in Missouri, gain the Merrimac river, 
ebuseets ; Engelmann. | 
[Dr. Bigelow collected near San Elceario, on the Rio Grande, a Sagittaria which was over. 
looked when Dr. Engelmann revised the genus in my herbarium in 1856. It seems to be the 
same as a plant from western Texas, which Dr. E. named, provisionally, S. longiloba, and which 
he regarded as very near S. simplex. We can find no sufficient characters for distinguishing it 
from that species. The leaves, however, are sagittate, with very long, narrow, and widely 
diverging lobes, a state in which we have never seen S. simplex. J. T.] 
