146 O. Hagstróm. 
3. Potamogeton ziziiformis Hagström, |. c., p. 99, fig. 3. 
Caulis ca. 1 m altus, ramosus teres, internodiis 4—7 cm longis; 
folia omnia submersa membranacea, margine scabra, medio 7-nervia lan- 
ceolata summum foliorum floralium subpetiolatum reliqua sessilia, bas, 
attenuato obtuse + conspicue cuspidata; caulina 80—100 mm longa 
10—15 mm lata, ramea minora, xj Ke mm; vaginae latae 25 mm longae 
nervosae obtusae subpersistentes ad basin costis humilibus; pedunculi 
subincrassati vel fere aequales 100—120 mm longi; spica primaria 8- 
verticillata 30 mm longa, stylus brevis stigma ut in P. gramineo (humilis 
ovalis); fructus non visus. 
Brazil, where it is collected 1892, by C. Lindman. 
4. Potamogeton dentatus Hagstróm, l. c., p. 101, fig. 4—-6. 
Caulis ca. 50 cm altus teres ramosus internodiis ca. 4—5 cm longis; 
folia omnia uniformia submersa membranacea lanceolata petiolata longe 
mucronata acute et minutissime dentata, quoad nervaturam P. lucenti 
simillima; folia caulina 7-nervia (nervis tenuissimis marginalibus exceptis) 
nervis longitudinalibus omnibus ad basin mucronis confluentibus, Ca. 
80 mm longa et 20 mm lata, petiolo 5—15 mm longo, mucrone plus 
: . 50—60 . D 
minus 10 mm, ramea minora, ^15 mm, mucrone petioloque breviorl- 
bus sed inter se eadem longitudine; stipulae intrafoliaceae 20—40 mm 
longae amplae membranaceae persistentes subfuscae  obtusae bicostatae 
costis ad basin stipulae crassitudinem ejusdem  6-plo superantibus; 
pedunculus inconspicue incrassatus 50—100 mm longus; spica deflorata 
50—60 mm longa; fructus parvus, 2 mm longus, 1,75 mm latus com- 
planatus suborbiculatus vel oblique obovatus, rostro brevi subapicali, dorso 
siccus subcarinato. 
Japonia: Yokoham, 10./22. aug. 1862. Maximowicz. Iter secun- 
dum. Mus. petropol. 
5. Potamogeton orientalis Hagstrôm, l. c., p. 102, fig. 7—8. 
Caulis ramosus tenuis compressus (= P. obtusifolio et Hilli), inter- 
nodiis brevibus, 5—35 mm longis, summo (spicae proximo) interdum ad 
40 mm; structura caulis cum ea P. Hillii conveniens; folia caulina line- 
aria, 50 mm longa 2 mm lata, in apicem acutum aequaliter et sensim 
angustata, ad apicem 3-nervia, medio 5-nervia; costa mediana utroque 
striis albidis duabus instructa; nervi laterales principales in medio inter 
costam mediam et marginem siti, marginales saepius tenuissimi, trans- 
versales pauci; folia ramorum minora obsolete 3-nervia acuta subcus- 
pidata; stipulae deciduae, 10— 15 mm longae; pedunculi rocti vel flexuosi. 
15—25 mm longi; spica 10 mm longa 3—4-verticillata subinterrupta: 
fructus et hybernacula desunt. 
The species forms a natural group with P. pusillus, obtusifolius, 
Hilü ete. which all have flexible leaves and differ from P. rutilus, mucro- 
natus eic. with stiffer leaves and more prominent nerves. 
Assam: Brahmaputra, 7. 1896, Dr. Kings Collector and from Japan 
R. Tama, Musashi, 1888, T. Makino. 
ER de II PICO A 
