Marine Plants of Nha Trang — Dawson 
441 
Fig. 51. a, b, Gymnogongrus fiahelliformh: a. Habit of a vegetative plant, X 1; part of a cystocarpic plant, 
X 1. r, Gymnogongrus pygmaeus: Habit, X 2.4. 
onies to 2 cm. high on rock surfaces, Sta. 6 
(11229). 
Although I have not seen any authentic 
material of this species, my plants agree well 
with Agardh’s description and with Kiitzing’s 
illustration of the type, except for being some- 
what smaller throughout. 
Gymnogongrus japonicus Suringar 1870: 
36, pi. 24A 1-4 (Kyushu, Japan) 
Fig. 52^ 
LOCAL DISTRIBUTION: Young cystocarpic 
plants forming a dense clump about 18 mm. 
high on the sea wall, Sta. 6 (11228, Feb. 2); 
older plants to 5 cm. high and more loosely 
branched (11453, Mar. 18). 
The older plants of these collections agree 
well with Suringar’s illustrations of habit and 
structure, although the medullary cells of his 
plants are shown to be somewhat larger than 
of mine. The dichotomous branching, narrow, 
compressed segments, blunt apices, and 
thickened, terete basal segments are dis- 
tinctive. 
Gymnogongrus serenei sp. nov. 
Fig. 52d 
Thallis ad 4 cm. aids, e pluribus laminis 
erectis, semirigidis, planis, subsimplicibus ad 
dichotomose ramificatis, ligulatis, hand stipi- 
tatis, e disco parvo; laminis 1.0-2. 5 mm. lads, 
300-400 ju crassis, baud frequenter ramificatis, 
plerumque intervallis 1 cm. plusve. anguste 
angulatis; marginibus integris; apicibus ob- 
tusis; antheridiis superficialibus in soris elon- 
gatis; cystocarpiis superficialibus, circiter 800 
IJL diametro, hemisphaericalibus. 
Thalli to 4 cm. tall, consisting of several 
