KUNGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 55. N:0 5. 37 



in N. J. Scheutz, Plantse vase. jeniseenses etc. 1888. Here the author states that 

 »P. pectinatus» was gathered by the Swedish Yenisei-Expedition 1876—1877 in the 

 forest territory at several stations (Yeniseisk, and so on, northward), in subaretie 

 territory two stations, and in territorium aretieum in several places as far as 

 Nikandrovskij-island and Tolstoi-nos to the north of the 70th° N. L., where speci- 

 mens many feet long were thrown up on the shore. 



Part of the material collected is P. subretusus, but another part, especially 

 these gigantic examples are made up of P. vaginatus, although they were all clas- 

 sified by Scheutz, to whom as to other Swedish botanists this species at that time 

 was not yet known, as P. pectinatus. 



The two latter species accompany each other in the Yenisei-valley as far as 

 the mouth of the river. In general both occur together in Asia in a region of va- 

 rying width, but P. pectinatus spreads southward, whereas P. vaginatus extends its 

 domaine towards the north until meeting with the P. subretusus, which evidently 

 is an inhabitant of the Tundra-lakes and estuaries of Arctic Siberia. 



At the Swedish coasts P. vaginatus therefore has arrived as an immigrant from 

 the east by Finland, whereas P. pectinatus, again, undoubtedly has immigrated from 

 the south. Having arrived at the Baltic very early after the ice-period as is proved 

 by the discovery of its fossil fruits, P. pectinatus must be considered to have long ago 

 reached its northern limit which is, in the Bothnian Gulf, the 64th° N. L., but in 

 Siberia a few degrees more on account of the high summer warmth of those regions 

 (at the mouth of the river Yenisei, for instance, according to Scheutz, ca. 20° C. 

 and above). 



As to the distribution of P. vaginatus farther westward, Ar. Bennett records 

 the species from Shetland (1887, W. H. Beeby, see the Journ. of Bot., 1907, 192!). 

 I am not fully convinced of the correctness of this statement. If it were true it 

 would be extraordinary that the species has not been found either in Norway, or in 

 the great lakes of Swedish Lapland, or in Iceland and Greenland. Consequently it 

 should have been brought direct from Canada or the Bothnian Gulf to Shetland ! 

 And again, Shetland, with an annual isotherm of about +7° C is situated too 

 far to the south of the boundary line of the species. Finally, there are in the 

 artide referred to other mistakes concerning the distribution of the species in ques- 

 tion, wherefore I suppose that closer researches on the Shetland vaginatus-]>lants 

 should be necessary. 



P. recurvatus n. sp. 



Caulis teres, superne (et a basi?) ramosus metralis, internodiis ut in praecedente, 

 6 — 12 cm longis, supremo ssepius infrajacentibus longiore (ad 12 cm). Folia anguste 

 linearia (1 — 1,5 mm) trinervia substriata canaliculata obtusa, apice ut plurimum re- 

 curvata, longissima, inferiora verisimiliter ad 50 cm longa, vaginis ad 14 cm longis 

 et ligulis albidis 15—23 mm longis, superiora sensim in longitudine decrescentia, 

 suprema (folia floralia) 5—12 cm longa, vaginis 7 — 15 mm longis. Vagince tenues 



