o: 
FERNS : BRITISH AND FOREIGN. 
Synanjium. 
The synangia are formed by the union of a greater or lesser 
number of exannulate sporangia, arranged side by side, forming a 
series of cells, disposed in a circle, or in two rows side by side, 
united in one mass, which either remain united (plate I. fig. 5), 
or separate longitudinally in two valve-like lobes (plate I. fig. 6). 
The cells open for the escape of the spores by a slit on their inner 
side or by a pore at their apex. 
In Lycopodiacece and Marsileacese there are two kinds of sporangia, 
the one containing numerous small spores, the other only a few — 
considerably larger. Some authors consider them to represent 
different sexes, and therefore named the first Antheridangia, the 
other Oophoridangia. The large spores are known to vegetate, and 
some say the small ones also ; the large ones are called Corpuscules. 
In the genus Marsilea the sporangia are called conceptacles, because 
they contain free vesicles of two kinds, one containing small 
spores, Antheridangia, the other large ones, Oophoridangia. 
3. Sorus. 
The sori are the masses of sporangia borne upon the recep- 
tacles, and are either naked or furnished with variously shaped 
hairs and scales, or with membranous or rarely coriaceous covers 
of various forms ( indusia ) ; their form and position correspond 
with and are dependent upon those of the receptacles, which are 
their foundations. Thus, when the receptacles are punctiform, the 
sori are always round (5) or globose, while elongated receptacles bear 
sori of many forms, oblong ovate, oval, elliptical, arcuate, linear (50), 
reticulated (54), &c. When situated on the margin of the frond or 
segment (marginal), a little within the margin ( antemarginal ), 
somewhere between the margin and the midrib { intramarginal ), close 
to the midrib ( costal or basal), or sometimes on a pedicel, and pro- 
jecting slightly beyond the margin ( exserted or extrorse) (73). In some 
cases they are irregularly scattered, but in others they are arranged 
either in rows ( serial ) (7) or in continuous lines, and when these 
diverge at an angle from the midrib they are said to be oblique (110) ; 
find when parallel with either the margin or the costa, transverse 
(90 and 100). As a general rule, each sorus is distinct and well- 
