SPHAGNACE^E. 



[ 590 ] 



SPHAGNOC2ETIS. 



3. S. elastica, Agardh. Dissepiments 

 conspicuous ; ordinary cells quadrate ; vesi- 

 cular cells elliptic ; spermatic cells cylindri- 

 cal, truncate. Ralfs, I c. pi. 8. fig. 9. Cy- 

 lindrospermum elongatum, Kiitz. Tab. Phyc. 

 i. pi. 99. fig. 3. Forming a tender stratum 

 of a deep bluish colour in bogs. 



** Filaments moniliform, spermatic cells 

 turgid, much broader than the ordinary 

 cells. 



4. S. Broomei, Thwaites. Filaments 

 elongated ; ordinary cells suborbicular j ve- 

 sicular cells barrel-shaped or elliptic ; sper- 

 matic cells elliptic, catenate. Ralfs, /. c. 

 pi. 7- fig- 10. Forming a firmish bluish- or 

 yellowish-green stratum in brackish ditches. 



5. S. Berkeleyana, Thwaites. Ordinary 

 cells spherical or slightly compressed ; vesi- 

 cular cells spheroidal, compressed, as broad 

 as the large, turgid-elliptic spermatic cells. 

 Ralfs, 1. c. pi. 8. fig. 11. In brackish 

 ditches. 



6. S. Mooreana, Ralfs. Ordinary cells 

 subspherical ; vesicular cells barrel-shaped, 

 much narrower than the large, broadly ellip- 

 tical spermatic cells. Ralfs, I.e. pi. 8. fig. 12. 

 An Irish species. 



*** Dissepiments obscure, cells longer than 

 broad. 



7. S. leptosperma (Kiitzing). Filaments 

 elongated, not constricted at the dissepi- 

 ments ; ordinary cells longer than broad, 

 confluent ; vesicular cells elliptic ; spermatic 

 cells linear. Ralfs, 1. c. pi. 8. fig. 13. Cy- 

 lindrospermum leptospermum, Kiitzing, Tab . 

 Phyc. i. pi. 99. fig. 2. Forming large shape- 

 less gelatinous masses in still waters, varying 

 from deep green to yellowish-green, or, when 

 the filaments are comparatively few, nearly 

 colourless. Distinguished especially by the 

 " confluent ordinary cells with obscure dis- 

 sepiments." 



BIBL. As above. 



SPHAGNACE^. A family of Opercu- 

 late Mosses of peculiar habit, growing on 

 bogs, &c., distinguished especially by the 

 mode of branching, the structure of the 

 leaves, sporanges and antheridia, and by the 

 absence of roots, except in the early stages 

 of growth. 



The stem of the Sphagna is composed of 

 three layers of cells, a cortical, a medullary, 

 and a prosenchymatous layer intermediate, 

 which finally becomes somewhat woody. 

 The primary axis is indefinite in its growth, 

 the lateral axes, sterile or fertile, are annual. 



The secondary axes are fasciculate, and being 

 pendent or recurved upon the stem, they 

 fulfil in some measure the function of roots. 

 The leaves are remarkable for the cellular 

 structure, being composed of two kinds of 

 cells, namely, narrow and elongated cells 

 filled with chlorophyll, conjoined into a kind 

 of network, the meshes of which are occu- 

 pied by large hyaline cells. The hyaline 

 cells contain in all but one exotic species, a 

 spiral or annular secondary deposit (PI. 39. 

 fig. 25) characteristic of this family. These 

 large cells also become opened by regular 

 circular pores at a certain stage of growth. 



The inflorescence is monoecious or di- 

 cecious. The antheridia are produced singly 

 in the axils of perigonial leaves at the club- 

 shaped tips of short branches. They are 

 pedicellate and roundish, like those of the 

 Liverworts ; they produce biciliated sperma- 

 tozoids. The archegonia are found about 

 four together, sessile, in a tuft of perichaetial 

 leaves occupying the axis of a fascicle of 

 branches ; the receptacle subsequently elon- 

 gating into a peduncle, bearing a globular 

 capsule, entirely surrounded by the calyptra; 

 the calyptra is ruptured near the middle, the 

 lower part persistent and continuous with 

 the fleshy vaginule, within which the capsule 

 is seated on a bulb -like pedicel ; peristome 

 none, operculum flattish, thrown off with 

 elasticity. Spore-sac wanting, columella 

 short, not reaching the mouth of the capsule. 

 Spores apparently of two kinds, some en- 

 closed four together in parent-cells, others 

 smaller, sixteen in one mother-cell, the 

 former fertile, the latter sterile, occurring 

 either together or in distinct capsules. 



British Genus. 



SPHAGNUM, Dill. Character that of the 

 order. Nine species occur in Britain, some 

 common on every bog, distinguished by their 

 brilliant yellow-green colour and the wet, 

 spongy character of the beds they form. The 

 leaves are very interesting microscopic ob- 

 jects. 



BIBL. Wilson, Bryologia Brit. p. 14; 

 Schimper, Ann. des Sc. nat. 4 ser. i. p. 313. 



SPHAGNOCLETIS, Nees. A genus of 

 Jungermannieae (Hepaticaceae), containing 

 one species, S. (Jung.) Sphagni, an elegant 

 little plant growing over Sphagnum and other 

 mosses on bogs ; attaching itself by long 

 radicles, numerous on the under side of the 

 procumbent, nearly simple stem. The gem- 

 miferous branches only have amphigastria. 



BIBL. Hook. Brit. Flor. ii. pt. 1. p. 113; 



