KUNGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 55. NIO 5. 



249 



Its nearest relation is, of course, P. dentatus, which differs by another, Zizii- 

 like anatomic stem-diagram, more lucens-\ike nervation and shape of leaves, shorter 

 petioles but longer cusps (± 10 mm each, in the stem-leaves), shorter (± 3 cm) ligules 

 with higher ridges and smaller, 

 gramineus-like fruit »2 mm lon- 

 gus, 1,75 mm latus complanatus 

 suborbiculatus v. oblique obova- 

 tus, rostro brevi subapicali, dorso 

 siccus subcarinatus», see Hag- 

 ström, New Potamogetons (Bot. 

 Not. 1908, 101-102, fig. 4—6)! 

 This species, again, differs but 

 little from P. Gaudichaudii of 

 Ladrone Islands, the original 

 specimens of which are no more 

 accessible (specimina originalia 

 desunt: Graebner). But I have 

 seen specimens from the very 

 locus classicus: Guam, Agana Ri- 

 ver, coll. by Mc Gregor, 1911 

 (hb. Haun.), that present stem- 

 leaves with a shorter cusp and 

 shorter ligules, 16— 18-flowered 

 spikes, no cortical strands in the 

 stem, except the ligular circle, 

 and a cc. of the oblong type. 

 Fruit not seen. 



P. malaianus prolongs 

 itself by branches of as far as 

 the 4th rank, but shows no 

 tendency to develop coriaceous 

 leaves. 



Distribution: Herb. E. 

 Fries (hb. Uppsal.) contains a 

 specimen without stated locality, 

 but obviously identic with the 

 Teysmann specimens, of Halma- 

 haira. — Japan, Jokohama, 62, 



Maximowicz (hb. Stockholm., Petropol.); Tokyo, 84, Makino (hb. Petropol.) — 

 Mandshuria »Flumen Mudandsian, fl. Sungari infl. in rivulo Saling tun. Provincia 

 Kitin», leg. V. L. Komarov (hb. Petropol.). — The distribution-area seems to be 

 the Malayan and Japanese Archipelago and adjacent countries, where P. dentatus 

 also obviously has its spreading. 



Fig. 115. A — E, P. malaianus Mig. A, Stem-leaf with appendant ligule, 

 }. B, Pistil, sideview, ' T 2 . C, Fruit, sideview, a £. D, Part of the transverse 

 section of stem, about ^ , ep epiderrais, hp, pseudo-hypoderma, vb, vaac. bund- 

 les, cc, central cylinder. E, Longitudinal and tangential section of epidermis, 

 7 i 6 . F — /, P. dentatus Hagstb., E, Stem-leaf with appendant lignle, nat. size. 

 G, '{. H, Part of the transverse section of stem, about C , B , lettered as at D. 

 I, Epidermis drawn as E; the same showing also the stem-epidermis of P. 

 Oattdichuiulii Chait. & Schl. and P. liicens L. V 5 - 



K. Sv. Vet. Akad. Handl. Band 55. N:o 5. 



32 



