But, in their essential structure, they very closely resemble the earliest Lepidodendroid trees of the coal: their stems and leaves are similar; so are their cones; and no less like are the sporangia and spores; while even in their size, the spores of the Lepidodendron and those of the existing Lycopodium, or club-moss, very closely approach one another.

Like many other rock-loving species, it produces spores in abundance, having no other effective means of spreading, and its fertile fronds are much more numerous than the sterile ones, and begin to fruit when very small.

Vaucheria has, however, a second and far higher mode of reproduction, viz., by means of fertilized cells, the true oospores, which, lying dormant as resting spores during the winter, are endowed with new life by the rejuvenating influences of spring.

Experiments have shown that separated spores from crushed smut balls lose their effective power in from two to three months, provided the soil is moist and loose, and in no case do they survive a winter.

Then taking each small pot separately, sow the spores on the surface and label them; do this with the whole number, and then place them in the pan under the bell-glass.

The brain of that man was the spore out of which was developed the modern steam-engine, and all the prodigious trees and branches of modern industry which have grown out of this.

The Adder's Tongue Family (Ophioglóssum, Botrýchium) has simple spore cases without a ring, and discharges its spores through a transverse slit (Fig. 6).

Osmunda Claytoniàna] The fronds have a bluish-green tint; they mature their spores about the last of May.

The sterile and fertile fronds are totally unlike, the latter not coming out of the ground until about July, when they appear like rows of small, green grapes or berries, but soon turn dark and remain erect all winter, and often do not discharge their spores until the following spring.

Each of these parts then secretes a cell-wall and becomes free as a spore by the rupture or absorption of the wall of the mother-cell.