S lurch. — ■. Harvey el la mirabilis ( Schmitz & Reink e). 99 
With regard to the relation of this plant to the average 
temperature, as indicated by its life-history, I have un- 
fortunately only been able to obtain the temperatures of 
the sea in Stokes Bay for a few months. As H. mira- 
bilis is usually found just below low- water-mark, I have 
taken the surface-temperatures close to the shore. They 
differ very little from the shore - temperatures taken at 
Plymouth, which I have copied from Mr. Church’s c Table 
of Surface-temperatures V 
[ 
Jan. 
Feb. 
Mar. 
jWBL ■ 
Apr. 
May 
June 
July 
Aug. 
Sept. 
Oct. 
Nov. 
Dec. 
I 
Plymouth 
(Church). 
7 
to 
8 
to 
6 
to 
8 
7 
to 
9 
8 
to 
10 
10 
to 
13 
12 
to 
16 
13 
to 
17 
14 
to 
18 
16 
to 
14 
14 
to 
12 
13 
to 
12 
to 
9 
Shore - waters in 
summer approxi- 
mate higher num- 
bers, the lesser 
being for open sea. 
Stokes Bay, 
Gosport. 
17 
i7-5 
17-4 
14*6 
Average temp, for 
each month. 
Vegetative 
Thallus 
- 
— 
— 
— 
— 
— 
— 
Tetraspores 
Antheridia 
Trichogynes 
1 Cystocarps 
(ripe) 
— 

— 
The host-plant Rhodomela subfusca is a perennial, producing 
a large number of new branches in the early spring. 
The spores of Harvey ella mirabilis are set free in February, 
March, or possibly as late as April. In October the parasite 
was very slightly developed, consisting of only a few filaments, 
none of which had reached the exterior of the host. It seems 
probable that the spore, after being set free, finds its way to 
a position between the cortical cells of the Rhodomela. It 
1 A. H. Church, The Polymorphy of Cutleria multifida, Annals of Botany, XII, 
1898. 
H 2 
