46 J. O. HAGSTRÖM, CRITICAL RESEARCHES ON THE POTAMOGETONS. 



f. devostitus n. f. — Folia brevia. Ramuli 2:ae et 3:ae ordinis vix evoluti. 



On account of the short leaves and the absence of short branches this form 

 presents a verv bare appearance. 



Distribution: Sweden, Scania Kullen (hb. Lund.). — Oothland, Bogevik, 82, 

 Andersson (hb. Lund.) 



f. brachypus n. f. — Differt a typo pedunculis brevissimis, 10 — 30 mm. 



Distribution. S. America: »Andes Ecuadorenses 1857 — 59, R. Spruce, N. 

 5886 (hb. Lund.), a narrow-leaved »P. striatus», see p. 52. — Besides in hb. »Stock- 

 holm, and Uppsal., labelled: >L. Kralik, Pl. Cunetanoo n. 136 et 395 >. 



f. coronatus Hagstr., Potamog. from As., in Bot. Not. 1905, 141: — Spica ssepius 

 multiverticillata (vertic. 5 — 8), fruetus minor, 3 mm X 2 mm. 



Distribution: High-Asia: »Muntjokk-ott 23 Juni Mapiek-köll» (hb. Stockholm. 

 Univ.) 



f. subirquabilis n. f. — Folia latiora, ramea et caulinia subsequalia. 



A rather broad-leaved form, with slight difference in width between branch- 

 leaves and stem-leaves. Recorded from England, River Leen, Mitchell (hb. Upp- 

 sal.) and from India, Panjab, Thomson (hb. Stockholm, and Uppsal.) 



f. tricAophyllus n. f. — Caulis tenuissimus, foliis trichoideis. 



Distribution : Spain, Iviza, Camberfeder (hb. Stockholm.).- Italy, Palermo, 

 Todaro (hb. Stockholm.). Besides in hb. Stockholm, labelled: »L. Kralik, Pl. Cune- 

 tanaa. N. 136, 1852 and 395». 



f. latiusculus n. f. — Folia praesertim inferiora latiora ca. 2 mm lata. 



Distribution: Sweden, Stockholm, 59, Zetterstedt (hb. Uppsal.). — Den- 

 mark, Omö, 64, Nielsen (hb. Uppsal.). England, Benwick, Cambs. 85, Fryer 



(hb. Stockholm.). 



Var. diflllMls n. var. 



Ramosior et plerumpue colore la?tiore pra? t er formas flumineas. Folia oninia 

 ramulorum sensim attenuata acuta; caulina inferiora, 0,5 — ca. 2 mm lata, obtusa 

 cum mucrone minimo verrucaeformi, media apice attenuata subacuta, summa angusti- 

 ora apice ± conspicue mucronata. — Fig. 18, A, B, C, D, L. 



This varietv has usually a lightei brown colour except the river-forms, t hat 

 are of a darker green. It is easily recognizable on the leaf-apex gradually tapering 

 to a keen point. The involucral and basal stem-leaves, however, always have their 

 fixed form. 



V. dijjusus is by far the most usual and widest sprcad form. In t lie Baltic 

 it can be considcred as comtnon. farther northwaids it is inoic sparingly niet with 

 in the south part of the Bothnian Gulf to »K varken». In the northern section of 

 the Gulf it is only recorded from Ratan, Sweden, under the 64:th N. L., and from 

 Jakobstad, Finland (C. VV. Fontell, Beiträge etc. 1909, 4) a little morc southwards. 

 To the north of the 04: t h paiallel it is not kiiown to me, but S. ALMQVIST (Haktm. 



