6 
INTRODUCTION. 
and filled with a delicate granular mass. It may also at times be observed that 
this mass is exuded at the last articulation, and surrounds this as a crust. These 
parts are frequently longer than the capsules, and are easily distinguished from 
the young capsules.” The late Professor Don, who wrote the above, adds — 
“ It is certainly probable that they are the stamina of Ferns, and indeed Link 
found them, after frequent search, in most of the Ferns which he submitted to 
microscopical examination.” Mr. Henderson, in an interesting paper on “ The 
Germination of Ferns,”* denies that there is any impregnation in Ferns, Mosses, 
or Equiseta ; yet, in an after paper read before the Linneean Society on ‘‘The 
Reproductive Organs of Equisetum,” completely confirms the above view. He 
states that he has found two kinds of granules in the unripe thecae of Ferns, 
Lycopodium, and Ophioglossum ; that the one kind is mostly absorbed during the 
maturing of the other ; and by submitting each to the test of iodine, he proved 
the one to be amylaceous or starchy — the other more of the nature of pollen. 
Thus the matter seems set at rest ; and as Mr. Henderson has found similar pollen 
granules in the thecae of Mosses and Jungermannise ; in the apothecia of Lichens; 
in the lamellae of Agarics, and in the perithecia of some other Fungi, his experi- 
periments assist much in elucidating other tribes, as well as that under especial 
consideration. 
Seeds or Spores, and their Germination. — The small, round, rough 
grains contained in the thecae, considered formerly as gemmae or buds, are now 
known as seeds, yet differing from common seeds in many respects. They have 
no cotyledons, but are a mass of cellular substance. Instead of sending upwards 
a plumule, and downwards a radical, from fixed points, they grow indifferently 
from any part of their surface ; that most exposed to light shooting into the 
future frond, while the deeper point propels the root. Owing to these differences 
the seeds have been called, not only here but in all the tribes of Cryptogamic 
vegetables, spores (or sporules) rather than seeds. They retain their vitality for 
many years, and those brushed from the dried plants of an herbarium will grow 
long after the specimens have been gathered, coming up first with a small crown 
or bud, from which soon issues a peculiar shaped frond not unlike that of a Lichen, 
or rather like that of Marcliantia, and differing much from the fronds of future 
growth. When this has expanded to a certain size, according to the species, the 
centre of it, both below and above, becomes thicker ; the lower part elongates 
into a root, while the upper part assumes a gyrate or circulate form, and gradually 
unfolds itself into an upright frond, of the same texture though much less divided 
than those afterwards produced. 
Theca and Sorus. — The spores in all the species are contained in capsules or 
thecae, each of which opens at a transverse irregular fissure, and is furnished with 
a jointed spring, nearly surrounding it, and by the elasticity of which the capsule 
is torn open and the spores dispersed. The thecce are collected into linear, 
oblong, or circular clusters, called sori, of which Professor Link thus writes :f — 
* *' Mag. of Zoology and Botany," v. I., p. 311). 1 •* Ann. of Nat. History," August 1810. 
