1912] -  LEWIS—ALTERNATION IN FLORIDEAE 241 
20 male, and 17 female. In the female plants ripe carpospores 
were being produced at the time of collection. Neighboring shells, 
as before, showed no Griffithsia. The contaminating species were 
Champia parvula (5 per shell), Lomentaria uncinata (4), Grinnellia 
americana (1), and Polysiphonia variegata (1). 
A very interesting feature of this culture was the occurrence 
of two large apparently hermaphroditic individuals. In each case, 
close inspection revealed the fact that the apparently single indi- 
vidual was really a complex of four plants in intimate contact at 
the base. The rhizoidal filaments were interwoven somewhat, 
but could be separated with needles. Of the four, two were male, 
two female. The four spores from one tetrasporangium of Grz/- 
jithsia frequently remain in contact after being shed, so that four 
spores may often be seen lying in immediate proximity, all derived 
from the same sporangium. In the cases mentioned, it seems as if 
this must have happened, and the four individuals composing the 
single compound plant have been derived from the four spores of 
a single sporangium. Further experiments will be made to settle 
this point. 
V. Dasya elegans.—Carpospores could not be obtained early 
enough in the season to give positive results. Tetraspores sown 
July 18, 1911, transferred to Fay Wharf July 109, shells collected 
August 14. The stand of Dasya was quite good, but the indi- 
viduals remained clearly separate, not running together at the base 
as in the case of Griffithsia. The largest specimens measured 4. 5 
cm. long, with 6 or 8 side branches from the main stem. The aver- 
age length was 2cm. Of the largest and best developed specimens, 
measuring more than 3 cm. in length, 6 were female, 7 male, and 
1 sterile. Of the total number of individuals, 139 were sterile, 
143 male, and 6 female. In interpreting this result, it is necessary 
to bear in mind that antheridia may develop when the plants are 
quite small (0.5 cm. long or in exceptional cases even less), while 
procarps do not begin to form in individuals less than about 3 cm. 
long. On control shells no Dasya developed. The most abundant 
contaminating species was Polysiphonia variegata, while Champia 
parvula, Ceramium rubrum, Chondria tenuissima, and C. dasy- 
phila, along with Enteromorpha sp., occurred rarely. 
