97 
New Potamogetons. 
By O. Hagström. 
In some herbaria we have found a number of Pota- 
mogetons hitherto being confounded with forms before 
known under other names. Most specimens examined un- 
fortunately have lacked ripe fruits by what, of course, 
their specific difference has been overlooked. In the most 
cases, however, the stemstructure affords a good help for 
identifying a form; and as to the following species and 
forms, they might rather easily be recognised by means of 
the added figures. For the present we are able to commu- 
nicate five new species and two new hybrids. 
Potamogeton parmatus n. sp. 
Caulis pedalis et ultra simplex feres, internodiis 6—10 
cm longis; folia natantia coriacea obtusa longe petiolata, 
petiolis foliorum floralium 13—25 cm longis, laminis medio- 
cris, 45—50 mm longis, 23 mm latis basi ovato, vel 60 mm 
longis basi lanceolato ; folia summa ovalia vel ovato-ovalia ; 
submersa membranacea cito putrescentia longe petiolata 
basi angustato; vaginæ deciduæ; pedunculus 5—12 cm 
longus æqualis; spica Horens 23 mm longa; fructus invisus. 
Anatomy of the stem : endodermis of 0-cells or faintly 
developed u-cells, two median bundles and consequently 2 
median channels, 1—2 (3) lateral bundles and channels on 
each side in the stele. Cortical bast in one circle, subepi- 
dermal strands few or none. This stemstructure differs it 
decisively- from P. poly-go nifolius, with which it has been 
hitherto confounded (Confer Græbner, Potamogetonaceæ 
in Englers Pflanzenreich IV. II. p. 66. 1907. and A. Bennett. 
Notes etc. in Annuaire du conserv. etc. de Genève. 1905. 
105). As for the stem-anatomy of P. polygonifolius, confer 
, Raunkiær, De clanske blomsterplanters naturhistorie. I. 1896. 
p. 45 ff. and fig. 18. B. pag. 49! From the epidermis-cells 
to judge its natural place, however, might be near to P. 
Bot. Not. 1908. 7 
