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Acrocystis nana Zanard. 



CHONDRIEAE (RHODOMELACEAE). 

 Nom. Jap. : Tsiikushi-Hodaiikiy 



PL VI-VIL 



Acrocystis nana Zanard. Phyc. IncL, 1872, p. 145, Tab. VIII, A, fig. 

 1-6 ； Schmitz u. Falkenberg* in Engler u. Prantl's Nat, Pflanzenfam. 

 I Teil, 2 Abt.， p. 4S0, fig^. 266 c ； Falkenberg Rhodomelaceen, p. 68? : 一 

 Okamura AI0-. Jap. Exsic, Fas に II， No. 69 ； 岡 村， 日本 藻類 名 ま， p. 232. 



Plants are p^regarious, lormino- irre^yularly roundish or trans- 

 versely stretched patches. Fronds are of hollow bodies, obovate or 

 pyriform in shape, standine" with short, solid and cylindrical pedilces 

 which arise sincr]y or subfasciculately from creepinp- rhizome, and 

 attain the heip^ht of about i cm. The rhizomes are cylindrical, scarce- 

 ly I mm. in thickness, and branch out without any definite order. 

 They are closely attached to substratum by emitting at first hair-like, 

 afterward more thickened, root-fibres. They send off branches up* 

 ward, the apical portion of which swells up at the beginning* into a 

 minute globular ball (Fig. 15). As the ball grows larger and larger, it 

 becomes obovate or pynform, beino- excavated within like a bladder 

 (Fig. 2). The apex of ball is round, and, when young, slio-htly 

 depressed. 



The pedicels of balls are very slip"htly narrowed at the neck 

 and are solid, internally consisting* of parenchymatic cells. The 

 structure ot pedicel is the same as that of rhizome. In the centre, 

 there passes a slender axis which is surrounded by 5 pericentral cells 

 of equal lenpth (Figs. 6， 10). Around the pericentral cells, there 

 are some layers of densely packed parenchymatic cells which are 

 covered by an epidermal layer. The intercellular spaces between the 

 axis and the pericental cells as well as those outside of the latter are 



