FKKMI -\\ A I i: K ALGJi OK T II K UNITED STATES. 67 



groundwork of the stratum. They appear to be unattached to the soil, and each filament 

 may be about hull an indi in length; but they are cuiuiuuiily found brukeu offal the inferior 

 eiitl. <>r tlu- lom-r pan decay* whilst tin- upper continues to grow. They are slightly curved, 

 in MTpful-liki- iu.-in..n. in \.-r quiii -iruigiit ; ut first they are Biui|>le, but now and then emit 

 lateral branch- . which i.-.oue at considerable angle* and generally iu pain. When a filament 

 is about tu branch, a rupture takes place iu the Hide of the sheath, and the endochrorne issues 

 iu two portion,, one connected with the upper, the -.ther with the lower half of the filament; 

 -' form the nurlri or im-dullary portion of two new branches and become duly invested with 

 ft meiiibrniiouti sheath, and gradually put on the aspect of the adult Glament. The einlo- 

 chronir j, granular, dark-brown, and annulated at short intervals, the transverse rings being 

 placed M ry i -l.i.i- to L 'i tlicr in the youngest portionx, and less closely in the older, where they 

 are distant from i-n.li otluT abont twice tin- diaim-t-r of the column. This annulated endo- 

 chrome i~ interni|>tri| at certain fixed places, where an ellipsoidal cell ia formed, separating 

 the endochroine of the lower from that of the upper portions." HABVKY. 



/,' murk*. I have ncvi-r scon cither tho genus or species, and therefore am 

 forced to copy the descriptions of both from Kubcnhorst and Harvey. 



FAMILY SmOSIPHONACE^E. 



Thallun ramoBos, e cellulia pachydermaticia aut nni Tel pluri seratis ct in vagina ampla inclusis 



f.inuaiiis, iiii.-riliini eellulis penlurantibus instructua. Kamificatio rera lit eelliilaruin vegetativarum 



i|iiaruniliun divi.jone in axis longitudinalis dircriionem, <|ua ex re cellule due sororie gignuntur; 



celluU inferior in trirhomatift continuitate permauct, superior divisioue contiuua rcpctita iu eandeni 



tioiirni . ml rainiiin e.xplicat. 



I'ropagatio adhuc ignota. 



Frond brnncheil, forim-d of thirk-walled cells in an ample sheath, sometimes furnished with liete- 

 r.iu uni- or mnlti-Rcriate. Branches formed by a longitudinal division of certain 

 evils, so as to form two sister cells; the inferior of which remains aa part of the trichoma, whilst 

 the other. l>v repeated divisions, grows into a branch. 



l'r-.ji:i'_'.nio:i not known. 



Remark*. The StrmiphonacetB are the most complex in their organization of 

 :ill tlir J'/ii/rocJiromrqihycece, in so far as the protoplasm within the sheaths is cvery- 

 wlicrr broken up into a number of distinct cells, each of which is provided with 

 a thick coat or wall as well as in the circumstance of the frond having more perfect 

 branching. The so-called pseudo-branches in the other families arc moie truly 

 comparable to distinct fronds or thalli remaining attached to the parent thallus 

 than to distinct branches, whilst among the sirosiphons the branches really belong 

 to the original thallus. The hetcrocysts are much more frequently absent than 

 present, only one of the known American species being furnished with them. 

 The sheaths are generally not so distinctly sheaths as among the oscillatoria, &c., 

 for. instead of being distinct tubes, they appear rather in most cases as masses of 

 firm jelly, the outer portion of which is hardened almost into a peridcrm, and in 

 the inner part of which the cells are imbedded. Their color varies from the 

 transparent colorlessness of glass to a dark opaque-brown. Their surface is per- 

 haps most frequently smooth, but at times is tuberculate or otherwise roughened. 

 I have never seen anything like spores about them. 



