S/ews mostly trichotomous, tlie lateral divisions short, and the general out- 

 line lanceolate. The minor branches and ramuli are uniformly whorled, 

 4-5 or more sprin<;in<i; from each node, atid generally the intornodes and 

 ultimate ramuli consist of single joints. Articulations cylindrical, or 

 the older ones thickened at each end ; the lower ones short, the medial 

 and upper ones many times longer than their l)readth. In the stems and 

 larger branches the nodn (coiinecling the calcareous joints) are sometimes 

 twice as long as the joint or internode, thread-like and horny ; in the smaller 

 branches they are short, and in the ultimate ramuli incons[)icuous. Cys- 

 tocarps are abundant both on the ramuli and the internodes of the larger 

 branches, and are usually secund ; very often they are so closely placed as 

 to form a row of unilateral tubercles. The colottr when living is a vivid 

 purple; becoming pale-red, and at length white in decay. The substance 

 is brittle, and the frond does not adhere to paper in drying. 



A very beautiful species of Amj)hiroa, allied to A. charoides, 

 but very much more slender in every part, more finely divided, 

 and ramulous. The whorls of slender ramuli somewhat resemble 

 small, multiradiate stars, whence the specific name. When in 

 fruit almost the whole frond becomes thickly warted with small 

 tubercles. 



The species is very extensively distributed along the Austra- 

 lian coasts, and so far as I have observed, it generally grows on 

 the rigid stems of the Cymodocea (or AmjjhiboUs), which it some- 

 times thickly clothes, to the exclusion of all other parasites. 

 The stems, so covered, seen waving under water have a very 

 beautiful aspect. 



Fig. 1. Amphiroa stelligera, — the natural size. 2. Part of a branch, with 

 whorled lesser branches and ramuli. 3. An articulus, with two ceramidia 

 from amain branch, after the lime has been removed by acid. 4. A tetra- 

 spo7'e : — variously majnified. 



