— 21 — 



cells are small and elliptical in cross section. It is also an interesting species 

 for observations upon pores. The inner surface of the branch leaves shows, e. g., 

 very characteristically the phenomenon of pores arranged in threes in adjacent 

 corners of hyaline cells, already alluded to in case of 5. erythrocalyx. If these 

 leaves are examined carefully from without and in various sections, the condi- 

 tions will be found to be as follows: at the point of union of three hyaline cells 

 there is often a common cup-shaped opening, amoundng to ^ or K the thickness 

 of the leaf; from the sides of this cup round pores enter each of the three cells. 

 Viewing these last pores from without the leaf one sees them at an acute angle, 

 which accounts for their often apparently narrowed shape and probably also for 

 the fact that WarnstorP speaks of them as "pseudopores " and I suspect also for 

 Russow's statement^ that the common walls of adjacent hyaline cells are perfor- 

 ated, allowing communication with each other. His explanation of how this con- 

 dition must have come about shows how near he was to appreciating the real 

 condition of things. , That there is such intercommunication of hyaline cells 

 at points where there is not at same time communication with the outside, i. e., 

 at points other than in cell corners I have not been able to demonstrate and see 

 no reason to believe. The same arrangement is present in other species, of 

 those already mentioned notably in S. erythrocalyx where Warnstorf again calls 

 the pores pseudopores, and less strongly marked in 5. papillosum where Warns- 

 torf does not make this mistake, and in fact in other species of Inophloea as well. 

 In all these, however, it occurs on the other (outer) surface of the leaf. On the 

 outer surface of the branch leaves of 5. compactum the phenomenon of pseudo- 

 pores is especially marked, i. e., along the commissures of the hyaline cells one 

 sees rows of markings suggesting elongated pores, but without puncture of the 

 cell membrane, the so-called fibril bands being reinforced by cross connections 

 in a way admirably described and figured by Russow.^ They are sometimes 

 well represented on the inner surface also and may be somewhat reduced on the 

 outer. The plants fruit not uncommonly and appear, at least in some cases, to 

 be monoicous, but further observations upon the antheridia are desirable. 



The species occurs under a variety of conditions in Greenland and along our 

 eastern coast from Labrador to Florida and Alabama, on the western from Van- 

 couver Island, northward to Alaska (Warnstorf accredits it to California, leg. 

 Bolander,'* but all of Bolander's specimens from California labeled 5. rigidum 

 which I have seen are 5. teres). Inland it is much less common and further 

 stations for it should be noted. It is similarly distributed in Europe and Asia 

 and appears then to be confined to the northern hemisphere where it does not 

 quite reach the tropics, but to the northward vies with the hardiest species. 



9. Sphagnum strictum Sullivant, 1846. This closely related species has long 

 passed under the name 5. Garheri Lesquereux & James, 1879, until Warnstorf in 



^ Pflanzenreich 51 : 146 and elsewhere. 



2 Zur Anatomie der Torfmoose 18; cf. pi V. fig. 58. 



^ Ibidem 9f. pi. I, fig. j, pi. V, fig. 61. The phenomenon had of course been noted long before. 

 ^ Cf. also Lesquereux & James, Manual 17. 



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