KUNQL. SV. VET. AKADEMIENS HANDLINGAE. BAND 55. N:0 5. 



225' 



two hybrids must therefore be kept 



I have also examined specimens from Lithuania labelled jP. salicifolius> 

 have been identical with another hybrid, P. litliuanims Gorski, but they 

 be regarded as authentic. These 

 ated from each other. Both are 

 crosses of P. perfoliatus: the former 

 .{salicif.) with gramineus, the latter 

 (lithuan.) with lucens, see below! 

 Consequently they have nothing to do 

 with P. alfinus, which everyone must 

 admit having once seen the true al- 

 pinus X gramineus. As to the hybrid 

 alpinus X lucens of which is spoken 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. litMianicus 

 Gorski. 



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

 With this form P. nitens p prcelongifolius 

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

 this again is P. nitens f. latifolius 

 TiSELius 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. siibtilis (Tis.) P. nitens ■( suhtilis 

 Tis., ]. c. n:o 47. — Very like the 

 precedent but with narrower leaves, 

 55—65 X 14—15 mm; peduncles often 

 stretched. 



which 



cannot 



separ- 



& • Fig. 107. P. nitens Web. [5 sithperfoliuliis (Raunk.) Hagstr. A, 



Polict Caulinij Habit-inulm-e showing the primary and soeondary involueral leaves, |, 

 a, iirimary spilte. B — //, rtubniersed stem-leaves, ], B, f. prtelongi- 

 fuUii.i (Tis.) HAOSTn., C, perfuHutifuliiis Tis., D, f. siMilis (Tis.) Hagstb., 

 £, f. fhiittineits Hagstu., F, f. iiiaritimiis Tis., G, f. Jacitum Hagstr., 

 //, f. bi-ei'ipes Hagstr. 



A similar form is the following 



f. fluiiiiiieus n. f. 

 submersa elongata ca. 80 X 12 mm, 

 basi cordata. 



The 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. extensu.s TiSELius in herb. Stockholm. — >>P1. internodiis longissimis instructa» 

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



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



