The Procarpium and Fruit in Gracilaria con- 
fervoides, Grev. 
BY 
T. JOHNSON, B.Sc. (London), 
University of London Scholar in Botany , 
Demonstrator of Botany in the Normal School of Science , S. Kensington . 
With Plate XI. 
f^RA CILARIA is one of the many genera of the Florideae 
described and beautifully figured in the { Etudes phyco- 
logiques’ of Thuret and Bornet. In this classical work the 
authors describe the secondary thickening of the thallus- 
branches and the unusual position of the antheridia ; and 
then proceed to discuss the structure of the mature fruits 
which appear on branches of the thallus as opaque, lateral, 
hemispherical swellings, consisting of an arched pericarp (fruit- 
sheath) formed by eight or ten layers of cells constituting the 
roof of a cavity, into which rows of spores radiate from 
placental cells occupying its floor ; the spores subsequently 
escape through a pore traversing the whole thickness of the 
pericarp. They then speak of the procarpium as follows : — 
‘ For reasons we have given in our “ Recherches sur la fecon- 
dation de^ Floridees,” it is very difficult to find the female 
organ unfertilised and without a fully developed pericarp in 
species with opaque tissue and with fruit not localised. This 
is just the case in Gracilaria confervoides , and although the 
cystocarps occur along the whole length of branches, and are 
often very numerous, we have never succeeded in finding the 
procarpia, and do not know their structure. In the youngest 
fruits we examined, the cortical layer showed already a 
thickening due to the multiplication of the cells forming it. 
[Annals of Botany, Vol. I. Nos. Ill and IV. February 1888. ] 
