V 



300 THE NOMENCLATURE OF POTAMOGETONS. 



name than Wolfgang's. Fries knew of the publication of Wolf- 

 gang's name (cfr. Nov. Fl. Suec. p. 26), and ignored it. I suggested 

 to Dr. Kihlman that Fries' plant should bear the name of Nolte, 

 but he declined to withdraw his name. Whether that is done, or 

 not, Wolfgang's must stand as the oldest name. I would here 

 propose that Fries' plant should bear the name of P. Noltei (after 

 one who closely studied the genus) when considered a species. 

 Almquist has already referred it as a variety to pusiUus in Hart- 

 man's Hand. Skan. Fl. ed. 12, p. 54, 1889. The plant of Wolfgang 

 has recently been found in Finland (Holmen, Kihlman, &c. !), and 

 I am indebted to Prof. Maximowicz, of St. Petersburg, for a 

 specimen from "Mongolia: Ordos. leg. G. N. Potanin, 1884," 

 under the name of P. gramineus L. var. mongolicus "Maxim. The 

 uncertainty attending some of Wolfgang's species has led to their 

 being relegated to " species dubise " ; but, where specimens exist, 

 the descriptions (incomplete undoubtedly) cannot be passed over. 

 The P. pumilus of the same author I believe to be P. Lonchites 

 Tuckerman, but I have not succeeded in seeing any specimen named 

 by Wolfgang. 



P. sibiricus, sp. nov. — " Potamogeton Siberia orient. 



ad fl. Wilni, 64°. Exped. soc. geog. leg. R. Maack, 1854," in 

 Herb. Acad. Petrop. C. J. de Maximowicz. Affinity with P. 

 obtusifolius M. et K., and P. acutifolius Link, the venation of the 

 leaves somewhat like the latter, fruiting spike like obtusifolius. 

 The nervation is also somewhat like that of P. ochreatus Eaoul, but 

 in that the whole of the leaf is nearly alike in structure, and the 

 nerves are connected by irregular zigzag transverse nerves ; in 

 sibiricus by straight ones at right angles to the other nerves, and 

 the central half of the leaf is distinct in structure from the other. 



P. sibiricus mihi. , — Stem compressed, 1 line broad, striated ; 

 with fascicles of leaves in the axils (much like P. Friesii has) ; 

 stipules obtuse, pale, 6-9 lines long, 1-1^ line broad ; nerves 

 numerous, slender, running almost to the apex without anasto- 

 mosing. Leaves all similar, sessile, linear, slightly narrowed to 

 the base, biglandular ; when young obtuse-mucronate, when mature 

 acuminate-acute; 18-24 lines long, 1-14; line broad, with 15-21 

 nerves ; the central portion of the leaf (one half) showing as a 

 distinct band, with the nerves much stouter, and connected by 

 transverse nerves at right angles to the others, the outer ones much 

 more slender, and only occasionally connected by transverse ones. 

 Peduncles 9-12 lines long, gradually but slightly enlarged to the 

 fruiting- spike; spike subglobose, dense, 12-16-flowered. Fruit 

 greenish yellow, rugose (probably not quite mature), 14; line long, 

 -| line broad, compressed, 3-keeled, with the central keel less 

 prominent than the outer ones, convex on the outer margin, nearly 

 half-ovate on the inner (the base of the fruit in a straight line with 

 the base of the beak), terminated by a stout recurved beak, with the 

 central process occupying a much larger space than in obtusifolius, 

 acutifolius, or Friesii. Embryo coiled to nearly two-thirds of a spiral. 

 Habit between obtusifolius and Friesii, easily separated by the head 

 of fruits from these and all other species known to me ; the heads 



