KUNGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 55. N:0 5. 



225 



which 



cannot 



separ- 



I have also examined specimens from Lithuania labelled »P. salicifolius » 

 have been identical with another hybrid, P. lithuanicus Goeski, but they 

 be regarded as authentic. These two liybrids must therefore be kept 

 ated from each other. Both are 

 crosses of P. perfoliatus: the former 

 (salicif.) with gramineus, the latter 

 (lithuan.) with lucens, see below! 

 Consequentiy they have nothing to do 

 with P. alpinus, which everyone must 

 admit having once seen the true al- 

 pinus X gramineus. As to the hybrid 

 alpinus X lucens of which is spöken in 

 the literature, nobody can yet pretend 

 to have seen it. 



A good figure of this form is to 

 be found in Reichenbach, Icones etc. 

 vol. VII, 1845, t. XXXI, f. 55. On 

 p. 19 it is, however, confounded with 

 P. lanceolatus Sm. and P. lithuanicus 



GORSKI. 



f. perfoliatifolius Tis., 1. c. ll:o 41. 

 With this form P. nitens [3 prcelongifolius 

 minor Tis., 1. c. n:o 46 coincides, and 

 this again is P. nitens f. latifolius 

 Tiseltus in Graebner, Potam. 1907, 

 90. P. nitens v. maximus Ar. Bennett, 

 Forms etc, in Journ. Bot. 1907, 173. 

 — Stem-leaves 60—70 (40—80) mm 

 long by ± 20 mm wide; base cordate. 



f. subtilis (Tis.) P. nitens 7 subtilis 

 Tis., 1. c. n:o 47. — Very like the 

 precedent but with narrower leaves, 

 55 — 65x14—15 mm; peduncles often 

 stretched. 



A similar form is the following: Fig . m . P nitens WjäB- p 8ubperfoliatus (Baunk.) hagstb. a, 



f fllllllilKMlS n f Polia CailHna Habit-pictare showing the primary and secondary involucral leaves, f, 



«, primary spike. B — //, Sabmeised stem-leaves, \, B, f. preetongi- 



submersa elongata ca. 80x12 mm, fou™ (Tis.) hagstb., c, perfoliatifolius tis., d, f. suums (Tis.) hagstr., 



. 1 E, {. fl aminens Hagstr., F, i. maritlmus Tis., G, f. lat-mun Hagstr., 



basi cordata. n, t ireoipes haostb. 



Tlie present form seems to be- 

 long to the rivers of South Sweden. Leaves of a darker colour than the preceding 

 which has very thin, membranous, light leaves. 



f. extensus Tiselius in herb. Stockholm. — »Pl. internodiis longissimis instructa» 

 ca. 100—250 mm; Folia caul. subm. ca. 50 — 60x7 — 10 mm. 



K. Sv. Vet. Akad. Handl. Band 55. N:o 5. 29 



