92 J. O. HAGSTROM, CRITICAL RESEARCHES ON THE POTAMOGETONS. 



P. strictifolius Ar. Bennett. 



Notes on Potamogeton, in the Journal of Bot., 1902, 148. 



According to the description this species comprises one barren form of the 

 Lake George, East Chicago, where it is detected by Rev. E. J. Hill, and one fruit- 

 ing form from Canada (Lake Scugog, Ont.). I have not seen the latter, but I have 

 examined Canadian specimens from Sea-Cow-Pond, Crane Lake, Assiniboia, Picanok 

 River, Quebec, and Ottawa River, Que., which seem excellently to answer to the 

 description of the fruiting plant of Lake Scugog. I cannot distinguish these specimens 

 specifically from P. fanormitanus. The barren form, again, which Rev. E. Hill has 

 had the kindness of sending me for examination, corresponds with P. foliosus so 

 eminently, that it must necessarily anyhow be connected with this species either as 

 a variety, or as a crossing. The latter supposition is the most probable, since the 

 nodes have oil -cells, lacking in P. foliosus, and the turios also are larger than in 

 this species. I know no other American species than rutilus, which with foliosus 

 would be able to produce such a form as P. strictifolius. The stem-anatomy also 

 supports this opinion in an unexpected way by the short epidermis-cells and the 

 extremely strong subepidermal bast-bundles, especially characteristic to P. rutilus. 



The epidermis lacks a pseudo-hypoderma, the bundles of the central cylinder 

 are fused into a compound one, and the stem is compressed just as in P. foliosus and 

 rutilus. The oil-cells of the nodes derive their origin from the latter. Leaves and 

 turios are intermediate between the two species. I am convinced that coming investiga- 

 tions concerning this barren form will confirm my assertion. P. rutilus has also its 

 distribution-area in the direction of the regions where P. strictifolius has been found. 



If the fruiting form of Canada should really be found to be a new species 

 separated from P. panormitanus, I propose that it may have a new name and that 

 the name strictifolius may be kept for the Indiana-form or, according to our asser- 

 tion the hybrid foliosus X rutilus. 



Distribution. N. America, East Chicago Lake, Ind., U. S. A. (hb. Stockholm.). 



P. rutilus Wolfgang. 



Ap. J. A. et J. H. ScHULTBS, Mantissa in vol. Ill syst. veg. C. a Linnb etc. 1827, 

 362. — P. pusillus var. B Cham. & Schlecht., Linnaea II, 1827, 172. — P. ccespitosus Nolte 

 ap. Reichb., Icones etc. VII, 1845, 15, t. XXIII, f. 41, nomen solum. — Fig. 1, K, 36. 



This beautiful species is well distinguished from all nearly allied by its stretched 

 turios with almost adpressed leaves. They appear as transformed branches in bud- 

 state or only transformed tops of older branches. The leaves are also very charac- 

 teristic partly by the form of the apex (Fig. 36, C) partly by their strong mechanical 

 strands appearing in the margin and along the three (or five) vascular bundles. 

 Two strong bundles are also to be found subepidermally in the lacunar system on 

 the lower surface and besides one or another thin strand as the fig. 36 shows. By 

 these facts the leaves obtain their well-known stiffness. The lacunar system is but 



