166 J. O. HAGSTRÖM, CRITICAL RESEARCH ES ON THE POTAMOGETONS. 



another species according to the author's description in 1892, which låter approved 

 is adopted by P. Graebner in his revision of the genus in 1907. P. sulcatm*. 

 therefore, has 30 — 36-nerved leaves, much larger fruits, longer spikes, and so on. 



P. muricatus is recognized by the broad-petioled ovate-lanceolate submersed 

 leaves, the broad short-petioled early appearing floating leaves, conspicuonsly elong- 

 ated styles and particular fruits (see the fig. !). The anatomic topography of the stem 

 has the following aspect: epidermis without a pseudo-hypoderma but with numerous 

 bast bundles, one circle of scattered interlacunar bast- and vascular bundles, 0-endo- 

 dermis and 8 free central bundles with strong bast-sheaths (in the fig. more strongly 

 hatched). In the trio the bundles are sometimes more fused, sometimes, again, more 

 free from each other, thus forming a transition to the foregoing group. Except those 

 bundle-sheaths there is no mechanic tissue in the pith. 



Distribution. Australia: »N. S. Wales, Major Vicary, 1836, 7» (hb. Stock- 

 holm.). Another station is: N. S. Wales, Tia River near Walcha, where it is gath- 

 ered by J. H. .Ma iden, 1897. 



P. sainarifonnis n. sp. 



Caulis liumilis teres simplex, ramo unico prolongatus. Folia submersa sessilia, 

 lanceolata, basi attenuata, apice obtusa, 7—9 cm longa, 7 — 10 mm lata, 7-nervia. 

 nervö medio non lacunosa, summa natantia ovalia obtusa obscure cuspidata, 

 basi ovata vel obscure cordata, 35—45 X 16 — 20 mm, 13- ner via petiolata petiolis 

 brevioribus (ca. 30 mm longis). Ligulcc tenues badiae decidua?, ca. 20 mm longa». 

 /'t dunculu8 teres, non incrassatus ca. 30 mm longus. Spiai deflorata 23 — 25 mm 

 longa, 7 — 8-verticillata. Pistillum stylo subalato conspicuo, stigmate ovali parvo. 

 FntcAus compressus, 3 X 2,5 mm, paone circularis, sinuosc alato-carinatus, rostrattis 

 rostro ålat o. 



The anatomical diagram of the stem is characterized by an epidermis without 

 psmdo-hypoderma, numerous subepidermal bast-bundles but no cortical strands, 

 0-endodermis and an eight-bundled central cylinder. 



The plants here concerned might be mistaken for /'. similia A. Benn., but 

 differ by longer submersed leaves which are 7-nerved and obtuee, by the absence of 

 a lacunar areolation along the midvein, by the even pedunele, and by the fruit lacking 

 bosses at the base. 



I havc scen sprcimens ouly from »Nov. Holland, austr.. Dr BeEB», coll. by 

 l'\ MÖLLER (hb. Kristiania), iianicd /'. natans R. Bb. 



I*, tricarinatns P. Muller & Ab. Bennett. 



In the Journal of Botany, is<.)i\ 2l>«>. 



The stigma of t his speciea is oblong and as to about halt' its length free from the 

 »tyle (see lig.'). The stem ånatomy does not ösaentially differ from t hat of the 



