Boodleae 257 



&gagropila-like clumps. Struvea elegans Borges. occurs in deep water down to 40 

 metres, and may become 10 cms. in length by 4 cms. in breadth ; St. anastomosans (Harv.) 

 Piccone frequently occurs in dense tufts in the fissures of rocks, the tufted habit being 

 due to the numerous erect growths from the rhizome-like branches. Chamaedoris 

 Peniculum (Sol.) O. Kunze occurs from shallow water down to 50 metres, at which depth 

 the stipe may reach a length of 15 cms. and the expanded head a diameter of 10 cms. 

 Apjohnia is a southern type known from Australia and the Cape. 



The genera are : Chamsedoris Montague, 1842 ; Struvea Sonder, 1845 ; Apjohnia 

 Harvey, 1855 ; Siphonodadus Schmitz, 1878 ; Ernodesmis Borgesen, 1912. 



Sub-family BOODLES. This sub-family is characterized by the irregularly 

 branched filaments, the branches as a rule growing out in all directions. In 

 Cladophoropsis the branches are often twisted together and the plants form 

 jfigagropila-like clumps on rocks, on other Alga?, or lying loose on the 

 bottom. The attachment to the substratum is effected by branched and 

 septate rhizoids. In Boodlea opposite branches may occur, and when this is 

 repeated in the branches of the second and third order a Struvea-like appear- 

 ance may result. In most cases, however, the ramification is very irregular 

 and new adventitious branches contribute to it (Borgesen, '13). The branches 

 are to some extent bound together by ' tenacula,' which may or may not be 

 cut off by a wall, and which grow out from the apices of the ccenocytes in 

 Boodlea, but from the sides of the filaments in Cladophoropsis. 



There are no annular constrictions at the base of the segments, and the 

 thin cell- wall is not stratified. The coenocytes divide by segregative cell- 

 division similar to that in Struvea and Chamtedoris. Small lentiform cells 

 occasionally occur on the inner walls of the coenocytes, very like those found 

 in Valonia, and from them branches may grow out. The thallus of Petrosiphon 

 is encrusted with lime. 



The parietal plate-like chloroplasts are very numerous and somewhat 

 polygonal, being joined together in the young coenocytes by very fine pro- 

 longations and thus forming a network. In older parts of the thallus the 

 connections disappear and the chloroplasts are separate, each usually with a 

 central pyrenoid. 



The genera are : Boodlea Murray & De Toni, 1889 ; Cladophoropsis Borgesen, 1905 ; 

 Petrosiphon Howe, 1905. 



Sub-family ANADYOMENE.*:. In this small group the thallus is irregularly 

 frondose, flat or basin-shaped, and consists of a leaf-like expansion of indefinite 

 outline. It is fastened to the substratum by numerous thin-walled rhizoids 

 which are mostly unbranched. Microdictyon is prostrate and sessile, but in 

 Anadyomene the rhizoids grow alongside each other and form a short stalk, 

 which broadens out at its base into a small disc composed of the irregular 

 coralliform lobes of each rhizoid. The thallus recalls that of Struvea, but the 



w. A. 17 



