
520 FERNS. 
The ferns are furnished with roots, horizontal or else up- 
right stems, leaves technically called fronds, because they 
are not veritable leaves, and which usually rise from the 
ground curled up compactly, and gradually uncurling or 
unfolding and expanding laterally and longitudinally, while 
on the backs of them little pustules, or else uncovered spots 
filled or packed with a finé dust, are seen. Almost every- 
body supposes these dust-like heaps are the seeds, but the 
magnifying lens show that each particle of dust is a curious 
little casket, or box, or pocket, held together by a jointed 
and elastic ring. There are many modifications of this ar- 
rangement, but in a vast number of instances such is the 
normal rule. When sufficiently mature and ripe, the ring 
_ bursts, and the finer dust is thrown out of the little pocket. 
Each of these grains of finer dust is, in effect, a small living 
bud or bulb, and if sown on moist earth, or even on a piece 
of moistened sandstone, wetted window glass or sandy soil, 
will soon vegetate and grow, and produce a little dark green 
thin scale, deeply divided on one side, and when magnified 
it will be found to be a mesh-work of delicate cells. This 
scale is called the prothallus, and is totally unlike any organ 
in the higher plants. The prothallus on having obtained its 
full growth, will have attached itself to the soil or substance 
on which it has grown, by tufts of minute roots, and in one 
or more of its tiny cells, a sort of bud has been formed, 
which presently protrudes itself from its mother cell to meet 
little bristly-threaded filaments, which are endowed with 
motion, and which have issued from other nourishing cells 
on the same prothalline scale. After uniting, the first-named 
bud or buds grow into tiny stems, having roots of their 
own, when the scale or prothallus perishes, the young fern 
pushing forth its leaves, at first very small and unlike the 
subsequent and normal ones. In a year or more (perhaps 
even many years) the fronds assume sufficient strane 
vigor and size, to make the pustules and heaps of pe a 
their backs, and the cycle of existence is complete. 
BGs Sr Ee 1, TA E pa L E ERT 


