MACLOSKIE: POTAMOGETONACE/E. 149 



Eur. and N. Am., in ponds. 



5. P. JUNCIFOLIUS Kerner. 

 In N. Fuegia (P. Dusen). 



6. P. LINGUATUS Hagstr. n. s. 



Stem rigid, emitting near the floral leaves a spiciferous branch with 

 coriaceous leaves. Internodes equal in length, 4-5 cm. Submerged 

 leaves thin, entire, lanceolate-lingulate, obtuse, the lateral principal nerves 

 connected with the midnerve half way up. Floating leaves coriaceous, 

 oval-subcordate, petiolate, with persisting, 2-costate stipules. Peduncle 

 7-10 cm.; spike 3 cm. Fruit dorsally carinate when dry and apically 

 subrostrate. 



S. Patagon. 



Caulis 30-50 cm. altus, rigidus, teres vel subteres, 3-7 mm. crassus, ad folia floralia ramum 

 spiniformem foliis vere coriaceis emittens, ceterum simplex vel vix ramosus ; internodia fere 

 aequilonga (4-5 cm.) ; folia submersa tenuia, integerrima, lanceolato-lingulata, obtusa, lamina 

 9-10 cm. longa et 2.5-3.5 ' ata . petiolo brevi (10-25 mm.), nervis lateralibus principalibus fere 

 ad medium folii cum costa centrali connexis ; folia floralia longe petiolata (8 cm.), ovalia, vix 

 coriacea ; folia natantia coriacea, obtusa, ovali-subcordata, longe petiolata, lamina c. 8 cm. longa 

 et 3.5 cm. lata; stipulae 4-6 cm. longae, persistentes, bicostatae, costis validis, ad basin stipula- 

 rum valde prominentibus (costa crassitudinem stipulae 3~4plo superans) ; pedunculus 7 cm. 

 longus ; spica mediocris, 3 cm. longa; stigma parvum, ovale (ut videtur) ; fructus 3.5 mm. lon- 

 gus et 2 mm. latus, apicem versus in parte dorsali siccus, conspicue carinatus, lateribus convexis, 

 apice inconspicue rostrato. 



Hab. Patagonia australis, Kark. (30/3, 1899). 



7. P. NATANS Linn. 



Floating leaves on long stalks, ovate-elliptical, many-nerved, cusp- 

 pointed, basi-cordate. Submerged leaves reduced to bladeless petioles. 

 Stipules long. Spikes cylindrical ; achenes large, 4.5 by 2.5 mm., pitted 

 on the sides, grooved on the back. 



(Temperate N. Am. and Eur. ; Chili) ; W. Patagon. and E. Fueg. (P. 

 Dusen). 



8. P. PECTINATUS Linn. 



Leaves all submerged, setaceous, alternate upwards, i -nerved; stipules 

 half adnate, scarious-margined ; peduncles filiform ; flowers verticillate ; 

 stigma capitate on a short style. Fruit obliquely obovoid, scarcely keeled. 



(N. Am. and Eur. ; Cuba; Andes); S. Patagon. (Hatcher). 



