FKI:>H \v A i I:R ALU, EOF THE UNITED STATE s. 73 



flpecimons collected in the month of Aumi-t, which grew on boards over which 

 spring water was constantly miming. These .specimens agree perfectly with the 

 otln T-. ezi '-pt that the filaments are larger und the elongated apical cell is wanting; 

 differences which 1 helieve to he due to the specimens collected in August being 

 older than those tir>t recei\ed. 



Fig. 2 a and '2 /', pi. '.', \\ere taken from the t\pes, whilst fig. 2 c, pi. 9, from the 



st >pe( illiclis. 



o. Cfllulx ]>lfrumi]tie in terie duplici vcl multijilici. 

 a. Ci'lU generally in double tenet, or multiple tenet. 



8. arffillaceus, WOOD, (sp. nor.) 



;i\-> tfimi. rxpanso, subnigro, submembranaceo ; trichomatibas brevihun, dense intricatig 

 et snpe noimiliil coiirrrtis, ramosia, irregularibus; ptteudoramulis brevibns, varie curvatix, 

 nuiiiiiliil rijriili-i, plrruin<|iii! awviulrulibua, apice nonnihil attrnuatis; cellulis subglobosis, 

 stepo compre88J8, plcrumqne in serie simplici ><! interdum in eerie duplici, vel rare multiplici ; 

 (Hulls ii|iicalilius valde elongatix, cyliinlricis, ftcjtouemn trichomatibus internis Bimiliban; 

 Taginis craesi.-, linnis. in trichomatilius maturis saturate rubido-brunneis, in rainulis sepe luteo- 

 lirunueis ct in apice hvulinis vt fere colons ezpcrtibus; cellulis pcrdurantibus nullis. 



Diam. if,," - .000833". 



Hub. In palude argillacea, Sonth Carolina. (Ravenel.) 



mi thin, expanded, blackish, submembranaceons; filamentfl short, densely intricate, and 

 i"ivi|iii-nily somewhat concreted, giving origin to nnmcroas branches, irregular; branchefl short, 

 variously curved, somewhat rigid, mostly ascending, apex somewhat attenuate; cells sub- 

 globose, often compressed, mostly in simple series, sometimes in double, rarely even in multi- 

 ple ; apical cells elongate, cylindrical, resembling the inner filament of a scytonema ; sheath 

 thic k, linn, in the mature filament deep reddish-brown, in the branches yellowish-brown, at the 

 apices of the branches nearly colorless and transparent ; heterocysts absent 



Remark*. I am indebted to Prof. Ravenel for this plant, which was found by 

 him on a moist clay bank near Aiken, South Carolina, August, 1869. It forms a 

 thin, somewhat membranous, dark stratum, the filaments of which are so closely 

 united that it is almost impossible to tease them apart with needles. Neighboring 

 filaments are often united at the edges so as to form distinct bundles, and even 

 the branches are sometimes concreted, although, generally, as seen under the 

 microscope, they project from the mass in all directions. The surface of the fila- 

 ments is mostly rough and ragged with fibrillac and membranous projections. In 

 the older filaments the cells are often entirely absent. They are mostly single, 

 but sometimes multiple in the filaments ; in the branches they are often partially 

 double. The ends of the older branches are often broken and empty, whilst those 

 of the younger are rounded. The color of the cells, as I have seen it, does not 

 strikingly differ from that of the sheaths. 



Fig. 3 a, pi. 9, represents a portion of an old frond magnified 460 diameters, 

 and fig. 3 i, the end of a younger branch. No. 79. Collection of Ravenel, Aug. 

 1869. 



8. jnittiiln, WOOD. 



S. in maculis snbnigris, parvis, tennibns, plernmque rotnndatis, interdnm enormibns, dispositae; 

 trirhomatibns arete intertextis. ramossissimis, rigidis, intequalibng, snbcylindricis, nonnihil 



10 My. 1871. 



