Hypnum exannulatum

Hypnum exannulatum, from here.

Belongs within: Hypnum.

Hypnum exannulatum is a relatively rigid, often purplish moss.

Characters (from Dixon 1924): Plants usually relatively compact and rigid, pinnately branched, mostly of a deep, often purplish colour, typically but less commonly green or yellowish; leaves close, strongly falcate, twisted when dry, not rigidly circinate, glossy at back, frequently striate, especially when dry, strongly hooked at tips of stem and branches, mostly longly and finely acuminate from a wide base; nerve often strong, usually purplish brown, mostly reaching nearly or quite to apex. Margin almost always denticulate, especially near base. Cells frequently short and wide, but not constantly so, the auricular usually abruptly dilated and very distinct, large, rectangular, hyaline, inflated, mostly thin-walled, forming rather large, widened, inflated conspicuous auricles, often reaching to nerve. Dioicous, rarely autoicous.

<==Hypnum exannulatum [=Amblystegium exannulatum] D24
    |--H. e. var. exannulatum [incl. H. fluitans var. pinnatum] D24
    |    |--H. e. var. e. f. exannulatum D24
    |    `--H. e. var. e. f. stenophylloides D24
    |--H. e. var. brachydictyon [=H. fluitans var. brachydictyon] D24
    |    |--H. e. var. b. f. brachydictyon D24
    |    `--H. e. var. b. f. orthophylla D24
    |--H. e. var. falcifolium (see below for synonymy) D24
    |    |--H. e. var. f. f. falcifolium D24
    |    `--H. e. var. f. f. viridis D24
    `--H. e. var. purpurascens D24

Hypnum exannulatum var. falcifolium [=H. fluitans var. falcifolium; incl. H. exannulatum var. rotae, H. exannulatum var. stenophyllum] D24

*Type species of generic name indicated

REFERENCES

[D24] Dixon, H. N. 1924. The Student's Handbook of British Mosses 3rd ed. V. V. Sumfield: Eastbourne.