OF SOUTH AUSTRALIA. 
431 
In Mychodea terminalis the supporting cell increases in size considerably 
and becomes richly protoplasmic. After fertilization it unites with the 
auxiliary cell and forms a large crowd of gonimoblast filaments, and from 
these filaments grow out spore forming tufts of branches. In M. ramulosa 
a richly nutritive tissue develops, combines with gonimoblast, and then pro- 
duces a crowd of 'spore-bearing tufts of branches, most of the cells forming 
carpospores. 
In the Mychodeaceae the tetrasporangia are zonate and dispersed in the 
thallus, while in the Acrotylaceae they are zonate but in defined sori. 
Studies in the Mychodeaceae are, however, still comparatively defective. 
Family MYCHODEACEAE. 
Mychodea Harvey. 
Family ACROTYLACEAE. 
Acrotylus J. Agardh. Hermedya Harvey. 
Family PHYLLOPHORACEAE. 
Plants bushy, dichotomouslv branched, the branches cylindrical to mem- 
branous ; growth from a marginal or apical meristem producing a pseudo- 
parenchymatous medulla and a close cellular cortex; sporangia tetrapar- 
tite, formed in rows at right angles to the thallus surface, the contiguous 
rows forming a nemathecial sorus ; spermatangia developed on outgrowths 
from superficial cells; procarps present, the carpogenic branch of three 
cells carried on a supporting cell which serves as the auxiliary and also, 
with intermediate cells of the branch, forms sterile cells or series ; gonimo- 
blasts first growing inward, becoming interwoven with thin sterile filaments 
producing irregular masses of carposporangia without a definite sheath; 
sporangial or gametangial reproduction greatly modified in some species. 
Stenogramme Harvey. Gymnogongrus Mart. 
Family GIGART1NACEAE Kylin 1932. 
Plant plane or bushy, subsimple or branched, developing with an axis 
of several filamentous initials, the medulla ultimately pseudo-parenchy- 
matous, the cortex obscurely filamentous, the small outer cells in rows and 
containing chromatophores ; sporangia in sori in the blade, developed from 
branching rudiments, tetrapartite ; spermatangia formed in sori on the 
surface; procarps present, the three-celled carpogenic branch carried on 
a supporting auxiliary which after fertilization forms slender-branching 
gonimoblast filaments which ramify into the medulla and produce a diffuse 
cystocarp. 
Gigartina Stackhouse. Iridophycu$ S. and G. 
