INTRODUCTION TO CHYPTOGAMIC BOTANY. 135 



correct, each joiut of the terminal bundles of threads is a dis- 

 tinct female cyst. 



108. A number of Alga3 occur in warm climates, whose real 

 nature is masked by an abundance of calcareous matter. 

 These were formerly, with a few exceptions, referred as coral- 

 lines to the animal kingdom. Like the underground Fungi, 

 they vary much in structure, and have very different affinities. 

 Some of these seem to be closely related to true Gonfervce, 

 though often classed with Siphonew. Acetabularia, (Fig. 41,) 

 which in form and marking resembles somewhat Coprinus 

 plicatUis, bears a whorl of threads, united laterally into an 

 orbicular disc, seated on a delicate peduncle, with a few free- 

 branched threads springing from the umbilicus. Polyijhysa is 

 somewhat similar in the disposition of the component parts, 

 which are however free. Several sj)ecies, though firm, are not 

 calcareous. The genus Anadyomeiie differs only from Clado- 

 phora, in having its branched threads united into a membrane, 

 which exhibits the most elegant marking. Valonia consists of 

 large cells or sacs, which are simple or branched, and repeatedly 

 constricted. Whether there is a dissepiment or no at the con- 

 strictions I am unable to ascertain, but in Dictyosphceria, the 

 surface of which is marked with the outlines of hexagonal 

 cells, there are strong dissepiments. 



109. The typical species are distributed over the Avliole surface 

 of the globe, some of which luxuriate at the Cape, and in the 

 lower parts of South America, the smaller species ascending 

 to very high latitudes and altitudes. They abound in the 

 islands of the Antarctic, where they generally differ from 

 northern species. Gladopliora crispata, under various forms, 

 is extremely plentiful in India, descending as low as the banks 

 of the Ganges, where it forms dense woolly masses, studded 

 with Diatomaccce or Chantransia, exactly as it might be 

 found in the Thames. Though the northern species sometimes 

 attain considerable size, whether as regards thickness and 

 rigidity, as Conferva Melagonium, which Dr. Sutherland has 

 found five feet long, or denseness of mass, as Cladophora rupes- 

 tris, none of them can vie with Conferva clavata, or Clado- 

 phora mirahilis. The aberrant groups arc inhabitants of 



