Australian Chlorophyta — WOMERSLEY 
This is a smaller plant with narrower fila- 
ments than any other species of Chlorodesmis 
(see Egerod 1952: 377 for the other species). 
It differs also in having the branching re- 
stricted to the basal region with constrictions 
just above each dichotomy. 
Chlorodesmis pusilla n. sp. 
Fig. 4 
Thallus 0.5-1. 5 cm. high, densely tufted, 
dark green, with a base of entangled colour- 
less filaments with rhizoidal processes. Erect 
branches numerous, sparsely dichotomously 
or irregularly branched. Filaments 24-50 /x 
wide, linear but with undulate walls and 
usually constrictions shortly above the dicho- 
tomies, occasionally elsewhere. Cell wall thin, 
very slightly thickened at the constrictions. 
Chloroplasts dense, round to ovoid, 1-2.5 /x 
across. 
Thallus 0.5-1. 5 cm. altus, fasciculus, fusco- 
viridis, ad basem implicata filamenta sine 
colore et cum rhizoidibus. Rami erecti et 
multi, dichotomi aut irregulares. Filamenta 
24-50 /I diam., linearia sed undulata, con- 
stricta supra dichotoma. 
Fig. 3. Chlorodesmis australis n. sp. a. Habit of plant 
(X 11); b, detail of branching, showing constrictions 
above branch axil (X 150). 
389 
Fig. 4. Chlorodesmis pusilla n. sp. a , Plant with erect 
filaments arising from the rhizoidal base (X 11); b, part 
of a filament, showing undulating wall and constric- 
tions above branch axil (X 50). 
TYPE LOCALITY: Pennington Bay, Kanga- 
roo Island, South Australia (in a shaded, rear 
pool on a rough reef). 
type: AD (No. A 7020, H. B. S. Womers- 
ley, January 4, 1948). 
distribution: Known only from the type 
locality and from Vivonne Bay, Kangaroo 
Island (H. B. S. Womersley, No. A 15,460), 
in a shaded pool, south side of Ellen Point, 
August 29, 1950. 
This species is similar to C. australis but 
forms more distinct and denser tufts, with 
branched erect filaments, and the cell walls 
are undulate. 
B0rgesen (1925: 77) separated Pseudochloro- 
desmis from Chlorodesmis on the lack of true 
dichotomous branching and the lack of con- 
strictions above the point of branching. 
Branching which is not truly dichotomous is 
however found in C. hildehrandtii (see Egerod 
1952, fig. 9), and C. pusilla shows similar 
branching. The two species here described, 
C. pusilla and C. australis , show constrictions 
