1 14 Ford. — The Anatomy of 
be also correlated with its manner of life. In this case 
Ceratopteris can hardly be regarded as typical, and the 
development of its vascular system cannot form any basis for 
investigation as to the origin of the polystelic Condition met 
with in the Vascular Cryptogams. 
III. The Sporangia. 
The development of the sporangia, together with the ger- 
mination of the spores and formation of the embryo, have 
been very fully worked out and described by Kny 1 . In 
his Plate VIII, Figs. 1-19, he has figured the various stages 
met with in the development of a sporangium : the sporan- 
gium arises from a single cell ; walls arise in this, forming 
a triangular cell in the centre surrounded by a single layer 
of cells. The central one cuts off a two-layered tapetum and 
itself forms the archesporium ; this by division gives rise to 
four spore-mother-cells, each of which forms four spores. At 
a later stage the tapetal layers are absorbed and the spores 
lie freely in the cavity of the sporangium. In the figures 
given by Kny none of the earlier stages show the presence of 
an annulus, though this is frequently present in sections 
of young sporangia where the archesporium has not yet 
divided into the four spore-mother-cells. In Fig. 13 the 
annulus is shown in a sporangium containing the four mother- 
cells at a stage before the absorption of the two tapetal 
layers. The sporangia are scattered irregularly over the 
leaves; as a rule, near the apex of the leaf younger ones 
are found, but this is not constant, and sections of leaves often 
show a mature sporangium side by side with a very young one. 
IV. The Vegetative Buds. 
Ceratopteris reproduces itself largely by means of vegetative 
buds. These arise at the angles and at the lobes of all the 
leaves, the sterile as well as the fertile producing them in 
large numbers. Hofmeister 2 states that each bud arises from 
1 Kny, 1875, p. 49 . 
2 Hofmeister: see Sachs, 1882, p. 433 . 
