5, cell of 8. maerophyllwm with no spiral filament and many large pores ; 6, transverse section of the cells of a leaf of S. ctpribifolium : — all higlily magnified.
1. Sphagnum compaetvm, Brid., caule crecto rarnoso, ramis dense confertis, foliis iinbricatis concavis ovato-oblongis obtusis apice denticulatis, theca ovato-rotundata, pseudopodio brevi. S. compactum, Brid. Bryol. Univ. vol. i. p. 16.
Tar. /3, rig'ulum ; foliis subrigidis convolutis superue attenuatis apice patulis, pseudopodio gracili subelongato. Nees et Hornsch. Bryol. Germ. vol. i. p. 14. t. 2. f. 5*.
Tar. y, ovatum ; foliis patentibus ovatis subacutis.
Hab. Campbell's Island ; in bogs near the sea, both the varieties grooving together.
The variety y. ovatum may possibly be a distinct species, though we have not ventured to separate it specifically ; it differs from the usual state of the plant in the ovate, not oblong, leaves, which are more acute at the apex, with somewhat cartilaginous margins. Dr. Lyall's specimens, though fragments, evidently belong to a much larger moss than S. cymbifolium, Dill., with more tiunid branches. Of this species Bridel remarks, "a S. cymbifolio, foliis semper apice denticulatis, i.e. praemorsis, ut et toto habitu distinctissimum." The oblong leaves of var. /3 and the absence of the spiral fibres in the outer cells of the ramuli also appear constant peculiarities.
In this, as in some other species, it is not uncommon to observe the spiral fibres of the lower cells of the leaf disposed in a double or triple helix. The interposed circular discs are readily seen to he pores, from their strong similarity to the distinct apertures found on the cells of the ramulus. The outer cells of the branches seem analogous to the ordinary cellular tissue of the leaves, and the inner to their intercellular tubes ; whence the true position of the latter on the upper surface of the leaf may be inferred : whilst, on the other hand, the concavity of the foliage would lead to the supposition of their occupying the opposite one.
3. LEPTOSTOMUM, Br.
Peristomium simplex e thecse membrana interiore ortum, annulare, suberectum, indivisurn v. rarius subdentieulatum. Calyptra glabra, dirnidiata. Theca sequalis v. rarius gibbosa, oblonga, in apophysin spuriam obconicam attenuata.
1. Leptostomum gracile, Br. ; caule csespitoso subramoso, foliis oblongis subacutis piliferis inferioribus ovato-lanceolatis, theca pendula oblongo-cylindracea, operculo hemispherico. L. gracile, Brown in Trans. Linn. Soc. vol. x. p. 321. Schwa eg. Suppl. vol. ii. pt. 1. p. 12. 1. 104. Gymnostomum gracile, Hook. Muse. Exot. t. 22.
Hab. Campbell's Island; on exposed rocks, altitude 1200 feet, barren.
It is not yet proved whether the L. gracile and L. inclinans be really distinct. Our specimens agree with the former, in having a strong excurrent nerve ; they differ from it in the stems being densely matted with radicles, and from L. inclinans in the leaves not being contorted when dry and then - margins not revolute. There is a new and very well marked species in the Hookerian Herbarium, L. Bridgesii, Wils., MS., from Conception and Colchagua in Chili, in which the leaves are piliferous, with the nerve evanescent below the apex, the seta short, and the theca, instead of being pyriform, is widest at the base.
4. SPLACHNUM, L.
Peristomium simplex. Denies sedecim, per paria coadunati v. approximate longitudinaliter exarati, tandem rerlexi et plerumque theca? extus apprcssi. Calyptra campanulata, basi subintegra v. fissa, theca brevior. Theca sequalis, apophysata, exannulata.
