Ser. RiiODOSPEiiME^. Fam, lihoclomelacece. 



Plate CXCI. 



THURETIA TERES, iiarv. 



Gen. Char. Frond stipitate ; stipes filiform, inarticulate, branched ; the 

 branches bearing pinnatifid, compressed or flattened, midribbed and 

 penninerved networks, formed of confervoid, anastomosing ramelK. 

 Fructification : 1, urceolate ceramidia, springing from the midribs of 

 the network, and containing a tuft of pear-shaped spores ; 2, sub- 

 globose sticJddia, sessile on the lateral nerves of the network, con- 

 taining tripartite tetraspores. — Thueetia {Due.) ; worthily dedicated 

 to M. Gustave Thuret, one of the ablest and most successful inves- 

 tigators of the physiology of the Algse. 



Frons stipitata ; stipes fiUformis, inarticulatus, ramosus ; ramis in reticnla com- 

 pressa v. applanata costata et penniiiervia, e filis confervoideis anastoviosan- 

 tibus formata exeuntibus. Fruct. : 1, ceramidia urceolata, ex cosiis reticuli 

 enata, fasciculum sporanim pyriformimn cotitinentia ; 2, tetraspora triangule 

 diviaee, in stichidiis subglobosis ad mrvos sessilibm evolutce. 



Thueetia teres ; network compresso-terete, bi-tripinnatifid ; lacinise linear, 

 cylindrical, obtuse, without lateral nerves ; articulations twice as long 

 as broad ; stichidia ovoid, binate or ternate, springing from the mid- 

 rib, their prolonged apices passing into the threads of the network. 



T, teres ; reticulo compresso-tereti bi-tripinnatifido ; laciniis linearibus cylindra- 

 ceis obtusis enerviis; articulis diametro subduplo longioribus; stichidiis ovoideis 

 binatis v. ternatis pedicellatis, e costa exeuntibus, eorum apicibus infila reticuli 

 transeuntibus. 



Thueetia teres, Harv. Alg. Austr. Exsic. n. 114. 



Hab. South Astralia, Dr. Curdie. Port Fairy and Port Phillip Heads, 

 W.E.H. 



Geogr. Diste. South coast of Australia. 



Descr. Root spongy. Fronds densely tufted, 2-4 inches high, and as much 

 in the expansion of the branches, In-, tri-, or pluri-piunatifid, the laciniai vary- 

 ing from one to three lines in diameter, terete or compressed. Each frond 

 consists of a percurrent, continuous axis or main filament, which emits 

 lateral, distichous, opposite or alternate branches ; this axis and its brandies 

 are whorled throughout with closely placed confervoid ramelli, which spread 

 horizontally; these ramelli are formed on a dichotoraous type, but their 

 branches anastomose continually into the meshes of a loose, spongy network, 

 which thus imperfectly encloses the axis, and constitutes the visible frond. 

 The apices of the ramelli are free, and project from the surface of the spongy 

 branches of the network. No ceramidia have yet been observed. The stichidia 

 are developed in the bases of the anastomosing ramelh, constituting the net, 



