WRANGELIACE^. hi 



Order IX. WRANGELIACE^E. 



Wrangeliece, J. Ag. Sp. Gen. Ord. Alg. vol. 2, p. 701. Part of Ceramiacece, J. 

 Ag. Alg. Medit. p. (59. Endl. Zd. Suppl. p. 34. Harv. Man. Ed. 2, p. 15G. PaH 

 of Callithamniece, Kiitz. Sp. Alg. p. G64. 



Diagnosis. Rose-red, filiform, articulate or inarticulate sea-weeds, furnished with 

 a monosiphonous, articulated axis. Sporlferom-7iucleus naked, formed of branching 

 spore-threads radiating from a fixed point, or whorled round minute lateral ramuli. 

 Spores pear-shaped, formed in the terminal cell of the spore-thread. 



Natural Character. Root a small disc. Fronds filiform, much branched, 

 alternately decompound or decompound-pinnate, the branches either opposite or 

 alternate, articulate or inarticulate, the inarticulate species traversed by an arti- 

 culated, monosiphonous axis, round which smaller stratified cellules are gradually 

 deposited. The younger portions of the frond in the typical genus are always con- 

 fervoid, or composed of a single row of cellules placed end to end in an articulated 

 thread. The cell-walls are thick, pellucid, and of a softish substance, soon decom- 

 posing in fresh Avater. The endochrome, when recent, is generally a brilliant I'osy 

 red or purple-lake tint, which is sometimes partially preserved in drying, but fre- 

 quently it becomes browner in drying, and in several species changes to a dark 

 brown or even black. This a good deal depends on the state of individual speci- 

 mens, as the shade of colour varies in the same species. 



The sporiferous nucleus is not enclosed within any conceptacle, nor is it immersed 

 in the frond, but exposed wholly naked, or at most surrounded with involucrul 

 ramuli, which close over it without contact. It consists of many branching spore- 

 threads, either springing in a globose cluster from the end of a shortened branch, 

 or whorled round the middle portion of minute, lateral ramuli. These spore- 

 threads at maturity bear on the branches solitary, pear-shaped spores, formed by a 

 transmutation of the terminal cells. The tetraspores are only known in some 

 species of Wrangelia. They, also, are naked, scattered along the monosiphonous, 

 confervoid ramuli, each tetraspore being formed of a ramulus shortened to a single 

 cell. 



At present this Order consists of two genera, one removed from the Ceramiaceaj, 

 the other from the Gloiocladeie. In the structure of the frond and in the whole 

 external habit, Wrangelia so perfectly resembles a Ceramiaceous plant that some of 

 its species have been, at different times, referred either to Griffithsia or to CalUtham- 

 nion, and so far as structure may indicate affinity there is a near agreement between 

 CaUlthaiimion and Wrangelia. But here tlie relationship ends, for the nature of the 



