Iodine Content of Algae — Grimm 
321 
TABLE 1 — continued 
SPECIES TESTED 
COLLECTION* 
SOURCEf 
MG. I’ll 
GM. ALGA 
PARTS PER 
MILLION 
Plum aria filicina (Farlow) Kuntz 
H 7681 
o 
1.25 
1250 
Plumaria hypnoides (Harvey) Kuntz 
H 1236 
O 
0.078 
80 
Plumaria sericea (Harvey) Rupr 
G . . . . 
M 
0.32 
320 
Polyides rotundas (Gmelin) Grev 
G . . . . 
M 
0.039 
40 
Polyneura latissima (Harvey) Kylin 
H 1147 
O 
0.039 
40 
Polysiphonia elongata (Hudson) Harvey 
G . . . . 
M 
trace 
trace 
Polysiphonia lanosa (L.) Tandy 
G . . . . 
M 
0.438 
440 
Porphyra naiadum Anderson 
H 1023 
O 
0.313 
310 
Pterochondria woodii (Harvey) Hollenberg 
H 1148 
O 
0.078 
80 
Pterosiphonia bipinnata var. robust a (Gard.) Doty . . 
H 1213 
O 
0.078 
80 
Rhodomela larix (Turner) C. Ag 
H 1033 
O 
0.156 
160 
Rhodymenia californica Kylin 
H 1196 
O 
0.078 
80 
Spermoth amnion turneri (Mertens) Aresch. 
G .... 
M 
0.313 
310 
Zanardinula andersonii Ag.) Papenfuss 
H 7674 
O 
0.039 
40 
Zanardimda filiformis (Kylin) Papenfuss 
H 7671 
O 
0.078 
80 
Zanardinula lanceolata (Harvey) De Toni 
H 7672 
O 
0.02 
20 
H 7673 
o 
0.059 
60 
Zanardinula lyallii (Harvey) De Toni 
H 7675 
o 
0.117 
120 
H 1050 
o 
0 
0 
* Collector: B, A. J, Bernatowicz; D, M. S. Doty; G, M. R. Grimm; H, L. Horowitz, 
t Location: B, Bermuda; H, Hawaii; M, Woods Hole, Massachusetts; O, Cape Arago, Oregon. 
treated remain for the most part in the herb- 
aria of the various collectors. The collector 
and collector’s number, where given, are 
shown in Table 1. 
As is shown in Table 1, very little iodine 
was detected in the Chlorophyta, a finding 
which is in agreement with the data of other 
investigators. Phaeophyta such as Laminaria 
and Desmarestia had the highest concentra- 
tions of iodine. However, these genera are 
large forms difficult to maintain in the labor- 
atory. Asparagopsis and Plumaria, both Rhodo- 
phyta, store iodine in considerable amounts 
and have the advantage of convenient cultural 
size. 
A variation of iodine content was found in 
different thalli collected from the same local- 
ity. For example, one sample of Laminaria 
agardhii collected from Woods Hole showed 
no iodine while other specimens of the same 
species from the same vicinity showed an 
accumulation of 5,000 parts per million. 
Turrentine (1912) records similar variations 
with L. saccharina. 
In a consideration of the iodine content of 
the same thallus, marked differences were 
noted by Turrentine (1912), Cameron (1915), 
and Black (1948). Fritsch (1945) reported 
that the greatest accumulation of iodine was 
in the actively growing cells at the base of the 
blade. Table 1 shows that the blades of L. 
sinclairii contained 5,000, haptera and rhizoids 
1,880, and stipe 3,750 parts per million. Iodine 
determinations of other species of Laminaria 
provided similar results. Thus, in Laminaria, 
there appears to be an analogy between the 
activity of growth-regulating substances ob- 
served by Williams (1949) and the distribu- 
tion and amounts of iodine present. 
Table 1 also indicates that two phases of 
Laurencia ohtusa contained different amounts 
of iodine — the yellow phase three times as 
much iodine as the green phase. The same 
appears to be true of two growth forms of 
Amphiroa fragilissima. A fine form contained 
more than five times as much iodine as a 
coarse form. A potential taxonomic use of the 
iodide test is suggested here as a supplement 
to the vague morphological criteria currently 
used in separating the infrageneric taxa of 
such genera. 
The data presented indicate that Asparagop- 
sis and Plumaria would be the most suitable 
species for further investigation. Their adap- 
