OF SOUTH AUSTRALIA. 
177 
Order RHODYMENINAE. 
CONSPECTUS OF FAMILIES. 
I. — Gonimoblast immersed in the thallus, adnate in the cavity of the 
cystocarp to a thickened placenta which radiates into the cavity ; the. 
thickened pericarp perforated at the apex. 
Sphaerococcaceae. 
Gonimoblast hemispherical-convex, much branched, compact and con- 
fluent; carpospores single or in chains on the apices of the branchlets. 
Tetrasporangia cruciately or zonately divided. 
Rhodymeniaceae. 
Gonimoblast divided into several successive lobes; carpospores evolved 
from almost all the cells of the lobes. Tetrasporangia almost always 
cruciately divided. 
II. — Gonimoblast sessile in the thallus, evolved within a cavity convexly 
elevated and covered by the cortex of the thallus perforated at the apex. 
Delesseriaceae. 
Procarps disposed in the middle stratum of the thallus. Gonimoblast 
adnate to a thickened placenta, lobes usually indistinctly evolved ; carpo- 
spores single or seriate at the apices of fertile branches. Tetrasporangia 
triangularly divided. 
Bonnemaisoniaceae. 
Procarps disposed in the cortex of the thallus. Gonimoblast adnate to 
a wide base, forming a much branched caespitulum; carpospores formed 
from the terminal cells of the fertile branchlets. Tetrasporangia 
cruciately, triangularly, or more or less irregularly zonately divided. 
III. — Gonimoblast affixed to the thallus by a pedicel or a broad base, i.e., 
altogether external or only included by the cortex in a varying way. 
Rhodomelaceae. 
Cystocarps attached to the thallus by a short pedicel or broad base. 
Gonimoblast evolved within the cavity open at the apex; carpospores 
single, or rarely in chains, on the apices of the fertile branches. Tetra- 
sporangia triangularly divided. 
Ceramiaceae. 
Cystocarps altogether external, or included in the cortex, naked or 
involucrated loosely by special ramuli. Gonimoblasts single or more often 
twin, mostly divided into several gonimolobes; carpospores formed from 
almost all cells of the fruitful caespitulum. Tetrasporangia triangularly, 
or less frequently cruciately divided. 
