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



251 



in distinction to the Nalantes and the Lucentes, the stone-cells of which are very 

 thick-walled and härd. — Leaf-apex of P. prcel. always cucullate and the margin 

 smooth. 



Anatomically P. prcelongus belongs to the species which are rich in sele re n- 

 chyma, while P. perfolialus, again, is a non-sclerenchymatous form and even lacks 

 the interlacunar ligular bundles in the stem-cortex. The former has consequently 

 very numerous bast-bundles in the stem as well as in the pedunele, in the midrib 

 of the leaf and in the ligules, to which may be added that P. prcelongus has also 

 a well developed w-endodermis in the stem, whereas P. perfolialus has o-endoder- 

 mis. Judging from these and other facts P. perfoliatus seems to represent a more 

 primitive type than P. prcelongus. 

 It approaches also obviously to 

 P. densus. 



It may be re mark ed that 

 among all known species P. prce- 

 longus has the longest peduncles, 

 as much as 65 cm long. 



From the fossil occurrence of 

 the two species in Scanian peat- 

 mosses it is clear that P. per\oliatus 

 has immigrated to Sweden almost 

 immediately after the melting of 

 the land-ice and that P. prcelongus 

 has followed rather close upon its 

 heels. 



P. prcelongus sometimes varies 

 with strongly recurved leaves: 



f. curvatus n. f. : Folia valde 

 recurvata. 



The forms can, besides, be 

 ranked to any of the following varieties: latifolius Alpers, brevifolius Celak., 

 angustifolius Graebner with both stem- and branch-leaves very narrow, and elegans 

 Tis. with elongated leaves, 210 — 250 X 20 mm, and long internodes above. 



Distribution. P. prcelongus occurs locally through the whole of the Scancli- 

 navian Peninsula as far as Alten and South Varanger in the Norwegian Finmark, 

 64, Henschen (hb. Uppsal.), and the Russian Lapmark, Nuortijaur, 83, Hollmén 

 (hb. Stockholm., Lund.) and Imandra, 92, Kihlman (hb. Stockholm.). 



The most northern Swedish localities are: North-Bothnia, Kengis, 31, L^estadius 

 (hb. Uppsal.), leaves green, elongated and narrow, 200x20 mm, labelled >P. grarni- 

 neum v. lanceolalum L^est. Vet. Acad. Handl., Kengis, 1831, sed semina nondum 

 visa. An nitens vestrum p. parte? Hartm. in Fl. scand. Ed. 2, praelongum sed per- 

 peram traxit». L/ESTadius has changed the name here to Aanceolatum^ instead of 

 »boreale* in Vet. Acad. Handl., probably in order to express the shape of the leaves : 



Fig. 116. A — F, Prcelongus Wtjlf. A, Lowest stcm-leaf, -J, showing 

 the form of the base of the 1 — i lowest leaves. B, Pistil, side-view, 

 >/-'. C, Transverse seetion of the fruit, f-, /, lid, /), pntamen, f, epicarp. 

 1), Part of a transverse seetion of the stem, \ s , showing the position of 

 the pseudo-hypodermal strands, str, ep, epidermis, hp, the two-layered 

 pseudo-hypoderma, il, intercellular lacuna, vb, vascnlar bnndle of the 

 lignlar cirele, inside which there are 3 — i circles of bundles, iv, inter- 

 lacunar wall. E, Surface seetion of the epidermis, \ r ' . F, Transverse 

 seetion of the lacunar portion of a fullgrown stem-leaf (lower half), ^j , 

 m, mid-bundle, vb, vase. bundlo, str, bast-bundles. G — II, P. perfolialus 

 L., G, Transverse seetion of the lacunar portion of an adult stem-leaf 

 (lower half), \ s (Obs! without bast-strands). //, Transverse seetion of the 

 fruit, ^, /, lid, p, pntamen, f, epicarp. (Cf. C!). 



