KTJNGL. SV. VET. AKADEMIENS HANDLINGAE. BAND 55. N:0 5. 233 



sjon Nossen (A. W. Lxjnd)» which he takes for »P. graminea X prcelonga^. More 

 closely examined this plant has later on (Hagstrom, in Netjm., Sveriges Fl., 1901, 

 797) been found to be a form of P. nitens Web. (see p. 226). 



A plant from Lunan Burn (Scotland) has also been thought to be the hybrid 

 gram. X prcel. Ar. Bennett has a note of it in the Journ. of Bot., 1907, p. 174, 

 but in the List of hybrids published by Rev. E. F. Linton in the same Journ. 1907, 

 p. 299, it is not further mentioned. 



That is all what literature has to state about a hybrid which in 1913 has 

 really been found in Sweden, at Boras in the Viskan river. 



In habit this plant reminds much of a low-grown P. prcelongus. The collector 

 has hesitatingly held it to be P. gramin. X perfol., from which, however, and from all 

 the forms of P. decipiens it is easily distinguished by its leaves. Branches mostly 

 sterile, zigzag-formed with numerous, very short internodes, especially upwards small- 

 leaved. Leaves rounded at the basis and cymbiform at the tip, which is somewhat 

 more narrowly contracted than in P. prcelongus. Topmost branch-leaves lanceolate 

 at their base or broadly short-petioled. All leaves with an obscure venation like all 

 Q'rammetts-hybrids and fewer-nerved than P. prcel. Margins smooth. Ligules inter- 

 mediate as to form and nervation, the nerves of the front-field not so much crowded 

 as in P. prcel. Peduncles of the specimens examined as in P. prcel. Spike sterile. 

 In a single spike, however, two fruits like those of P. prcelongus have been found. 



Stem-anatomy intermediate but multifariously varying as in all hybrids. Cen- 

 tral cylinder at the base of the stem more prcBlo7igiis-\ike, upwards, in the same 

 specimen, more like P. gramin. Endodermis always of M-cells like that of both the 

 parents. Cortical strands always fewer than in P. prcel., but more numerous, again, 

 than in P. gramin. Pseudo-hyp. one-layered (P. gram.) in some internodes, in others, 

 again, 2-layered, at intervals intermediate. Subepid. strands few or wanting {gra- 

 mineus). 



Habitat. Sweden, Boras in the Viskan, 1913, C. Sandberg and A. Holmertz. 



P. llicens L., Species pi., 1753, 126. 



P. lucidus GiJLDENSTADT, ReiscH, I, 1787, 76. — P. acuminatus Schum., En. 

 pi. Ssell., 1801, 49. — P. longifolius Gay in Lamarck, Enc. met. Bot. IV, 1816, 

 535. — P. volhynicus Besser in Roem. & Schult., S5^stema vegetabiL III, 1818, 

 509. — P. cornuius Presl, Flora cechica, 1819, 37. — P. caudatus Seidl in Opiz, 

 Boheims Gew., 1823, 23. ■ — P. macrophyllus Wolfg. in Schultes, Mantissa in vol. 

 Ill, 1827, 358. — P. Proteus lucens Cham. & Schl., Linn^a 1827, 197. — P. corni- 

 culatus ScHUR, Enum. plant. Transsilv., 1866, 633. — Figs. 1, H, 2, A, 110, 111, 

 115, /. 



This species always lacks coriaceous or subcoriaceous floating leaves and even 

 the tendency of producing such ones. On the contrary it has a prominent faculty 

 of reducing the size of the stem-leaves with the maintenance of the midrib-portion, by 



K. Sv. Vet. Altatl. ITandl. Band 5.5. N;o 5. 30 



