434 TJniversiiij of California PuhUcMions in Bofanj/ [Vol. (5 



type seems to be a species of Pleurooapsa, though being immature it 

 is not safe to attempt to place it. Possibly this is the plant which has 

 been considered to be a form of P. amethystea Rosenvinge (1893, 

 p. 967). 



Chlorogloea lutea Setchell et Gardner sp. nov. 

 Plate 36, fig. 1 



Coloniis in forma et in raagnitudine maxime variabilibus, super 

 superficiem hostis per partitione in planis duobus extendentibus, per 

 partitione in piano tertio (horizontali) pulvinulum cellularum ad 

 lOOjti crass,um formantibus, cellulis primo in seriebus verticalibus 

 ordinatis, tardiore dispositionibus verticalibus per partitiones in 

 planibus alteris evanescentibus, cellulis externis inordinatis ; cellulis 

 nonnullis lateris inferioris coloniae per partitiones horizontales in 

 hostem penetrantibus et ramos tortuosos per incrementum apicalem in 

 longitudine augentes formantibus, ramorum eorundem cellulis mox 

 in planis alteris quam horizontalibus partientibus et cellularum greges, 

 mox stipates et ultimo in greges solidas in centro coloniae coalescentes 

 formantibus ; cellulis 0.9-1.5/1. diam., angularibus, proxime (piadratis ; 

 cellulis apicalibus hostem penetrantibus ad 4ju. longis ; parietibus cellu- 

 larum hyalinis ; eontentu cellularum luteo-viridi, homogeneo. 



Colonies extremely variable in shape and size, spreading over the 

 surface of the host by cell divisions in two planes, divisions in the 

 third, horizontal plane forming a cushion of cells up to 100/x thick, 

 the cells at first being arranged more or less in vertical rows, but the 

 radial arrangement being soon destroyed by divisions in other planes, 

 the outer portion of the colony having cells arranged in no definite 

 order; by horizontal divisions certain cells from the lower side of the 

 colony penetrate into the host, forming crooked branched filaments 

 increasing in length b}^ apical growth ; cells of these filaments soon 

 begin to divide in other planes than horizontal, producing masses of 

 cells, encroaching upon one another, and finally coalescing into a 

 solid mass in the central portion of the colony; cells 0.9-1.5/a diam., 

 angular, nearly quadrate ; terminal cells penetrating the host, up to 

 4ju, long ; cell walls hyaline ; cell contents pale yellowish green, 

 homogeneous. 



Growing on the stipitate portion of Iridaea minor J. Ag. in the 

 lower littoral belt. Carmel Bay, Monterey County, California. May, 

 1916. 



Just wliere to align a plant like Chlorogloea lutea is a problem 

 more or less perplexing. It starts to develop on the surface of the 

 host plant, and if the cuticle of the host is sound in that particular 

 place, it develops a dense mass of cells of considerable dimensions 

 before penetrating into the interior. The plant at first spreads out 

 over the host bj^ cell divisions in two or more planes. It is impossible 

 to state the size of a single plant or colony, for in some places on the 



