Page:Journal of botany, British and foreign, Volume 9 (1871).djvu/14

 4 OBSERVATIONS ON THE SPECIES OF POTTIA.

Wilson (Bryol. Brit. p. 98) candidly admits that lie " dares not pronounce P. Starkeana and P. mbudula distinct ;" yet has kept the two forms in the presumed distinct genera. The scabrous calyptra escaped the notice of the authors of the ' Bryologia Europsea.'

4. P. Heimii, Hedw., easily distinguished by its leaves, varies greatly in the length of its capsule, but although frequent search has been made for a peristome, in promising specimens none has been found.

5. -P. lanceolata, Hedw. (^Anacalypta lcinceolata~), although described with entire leaves, has always some trace of minute crenation near where its nerve is excurrent from the apex of its leaves. This species is very variable in its peristome, when gymnostomous it is probably Gymnosto- mnm intermedium. Turner, and of Schwsegrichen, Supp. t. 7, a form com- monly referred to P. truncata, from which it may be distinguished by the crenation of the margin and rough cells of its leaves. The Desmatodon Giiepini (Bryol. Europ. DesmatodoH, t. 4) can hardly be other than a more complete form ; no character is given in the description by which it could be safely distinguished.

6. P. Cfvspitosa, Bruch, is unlikely to be confounded with any other species excepting P. Starkeana, and from this it differs immediately in the smooth calyptra.

7. P. trimcata, Bryol. Europ., may be truly Gymnostomnm. truncatnm, Hedw. Fund. t. 5, but Hedwig has figured and described his species as dioicous, — a fact which seems to have been overlooked ; it is certainly the G. trimcatum oi t\\e Bryol. Germanica, t. 9. f. 8. This species has acute entire leaves with smooth cells ; it varies greatly in its capsule, which is, however, always as wide at the mouth as it is lower down, and its usual form is turbinate ; forms with an elongated capsule are probably in herba- ria confused with the gymnostomous state of P. lanceolata. Mueller says in his ' Synopsis,' p. 554, that he has met with the peristome.

8. P. littoralis, n. sp. ; leaves oblong-subspathulate, obtuse or acute, the lower ones pale, the upper green ; cells in the upper part of the leaf about half the size of those of P. truncata, hence more obscure, smooth ; lower cells oblong, pellucid ; nerve excurrent, longer in the inferior leaves ; capsule oblong- oval, mouth less than the greatest diameter; operculum rostrate, slightly twisted ; male flower bud-like. Hab. Aldrington, near Brighton, Sussex, growing with P. Heimii, also at Hastings. The oval capsule, not dilated at the mouth, gives this Moss a greater similitude to P. lanceolata than to P. truncata, but from this it difiers in the smooth leaves. I formerly mistook this Moss for P. crinita, from which it differs in the quinquefarious arrangement of its leaves, and much shorter and more slender nerve, as well as in its smooth cells.

9. P. asperula, n. sp. ; leaves obovate-spathulate, acute, but not acu- minate ; nerve excuiTent into a short point, upper cells rounded, rather obscure, each with several elevated points, lower cells oblong, smooth, pellucid ; capsule oval ; operculum rostrate ; cells slightly twisted ; an- theridia naked in the axils of comal leaves. Hab. Henfield, Sussex, near Penzance, in several places, Mr. Curnow ; Jersey, M. Piquet ; also in Wilson's Muse. Brit, with P. truncata, n. 90. This has more obscure leaves than P. truncata, and when they are bent over under the microscope the roughness of the cells is easily perceived. The capsule is not so wide at tha mouth as it is about its middle. It is possible that this species may be sometimes confused with P. lanceolata, when that species is gym- nostomous, but it has many points of difference.

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