AND BUXBAUMIA. 347
Nearly the whole of these modifications exist in that natural subdivision of the order, which may be named Splachnece, consisting of Splachnum, Systylium, Tayloria {Hookeria of Schwaegrichen), Splachnum squamosum of Hooker, and Weissia splachnoides.
578] The number of teeth in Splachne^e is thirty-two, which, however, are never entirely distinct and at the same time equidistant, but approximated or united in various degrees in the different genera and species of the section.
Thus in Tayloria and Systylium the thirty- two teeth are distinct and disposed in sixteen pairs.
In Splachnum rubrum and luteum there are apparently only eight pairs, each tooth, however, having a pellucid and obscurely-perforated axis. In almost all the other genuine species of Splachnum there is the same disposition as in S. rubrum and luteum ; but the pellucid axis of each tooth is less distinct and imperforated.
In Splachnum anyustatum, and I believe also in a second species nearly related to it, the arrangement is somewhat different \ for the sixteen apparent teeth are approximated, and at the base even united in fours, the pellucid axis of each tooth being still less obvious. Hence these species in their peristomium very nearly approach to Tetraphis, to which they would be absolutely referable were the union complete.
In Splachnum squamosum the apparent number of teeth is eight, without any actual subdivision. But as each tooth has three equidistant pellucid lines, of which the lateral are nearly as distinct as the central, there can be no doubt that the composition is the same here as in the rest of the section. 1
1 In a late number of Musci Exotici, (No. 17, tab. 136,) Splachnum squar- rosum is transferred to Octoulepharum, and, on the authority of M. de Beauvois, is stated to be Octoblepharum serratum of Bridel. Mr. Hooker, however, con- tinues to refer it to this genus, on the supposition of its agreeing with the original species in the form of its calyptra : observing that if this should prove not to be the case, it ought to be separated, under the generic name Orthodon, formerly given to it by its discoverer M. Bory de St. Vincent.
The calyptra of O. albichim is represented as distinctly cucullate, both by Swartz (in Obs. Bot. tab. xi, fig. 1) and M. de Beauvois (in Flore J' tea re, i. tab. 31). I have also observed it of the same form in specimens from Madagascar. There seems, therefore, no reason to doubt that these two
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