14 
INTRODUCTION. 
for 1841, page 483, from which I extract the following remarks: — “The first 
external sign of germination is the appearance of four cells projecting through 
the apex. The enlarged cellular mass then distends the conical projection, 
and at length appears with four of its cells projecting beyond the general 
mass, and compressed into a quadrangular form. These projecting cells soon 
harden, and acquire a reddish-brown hue — soon after which little fibrillae or 
rootlets begin to shoot from one side. They are simply articulated tubes, or 
elongated cells applied end to end, each produced from one of the cells of the 
germ. The germ now gradually points in two places, which are by no means 
fixed, but occur in various situations, according to the position of the sporule in 
respect to light. These two points gradually lengthen, and if dissected, each 
will be found to consist of a closed sheath, containing in one instance the leaf, 
in the other the root, in the form of a conical process like a finger in a glove. 
Besides this sheath which embraces the upper part of the root, there is an 
exceedingly delicate expansion which closely embraces the extremity of the root 
like a cap. After the leaf has grown to be many times the length of the sporule, 
or about two lines long, another leaf grows from the germ close to the first, to 
which it is in all respects similar ; and then a bud begins to be developed from 
some indefinite part of the'germ, and like the leaves and root form within a sheath. 
This bud is covered by a peculiar kind of jointed hairs, whose attachments are 
lateral at a short distance from their bases.” 
Mr. Valentine then shows the origin and progress of the sporules within the 
theca, making afterwards the following pointed remark : — “ This account of 
Pilularia shows that it is incorrect to say of Acrogens that germination takes 
place at no fixed point, but upon any part of the surface of the spores ; for it is 
quite certain in this instance that germination invariably takes place at a fixed 
spot, which may be pointed out before germination has commenced.” This view 
exactly accords with some experiments I have instituted, and with the remarks 
of Dr. Lloyd, who read a most interesting paper upon this subject, before the 
British Association, in 1836. The statement in Lindley’s ‘ Nat. Sys.,’ ed. 2, 
page 416, that the theca never produces but one plant, is not correct, for if 
the theca be broken and its contents scattered, many of the spores will 
germinate. 
DISTRIBUTION. — “The solitary species of this order belonging to Britain is 
widely distributed, being found in Devon and Sussex, and extending at intervals 
from those counties northward to Sutherland. It is either frequently overlooked, 
or is otherwise a scarce plant in the south of England, increasing in plenty in the 
northern counties; probably the drier climate of the south-east of England, 
causing the small pools to diminish much or entirely to dry up in snmmcr, is 
adverse to the existence of a plant that is adapted to grow within the shallow 
margins of ponds and lakes. Of its range in altitude, little seems to have been vet 
ascertained.” — Mr. Watson's MS. 
