41 8 VASCULAR CRYPTOGAMS. 
» 
lower level between them or through the cicatrix of a leaf. They are not so 
numerous as those of most true Ferns, and they differ from them in their light 
colour, their more delicate structure and their greater thickness, peculiarities which 
they share with those of Ophioglossese. They ramify considerably in the soil, 
apparently in a monopodial manner. 
The leaves which in the smaller species attain a height of from one to two 
feet, in the largest {Aiigiopferis) of from five to ten feet, have a long firm petiole, 
channelled on its inner surface, which bears the compound lamina which is either 
pinnate or bi-pinnate, or palmate as in Kaulfussia. The primary petiole is attached 
to the basal portion by means of an articular swelling, and the secondary petioles 
are connected with it, the leaflets with their rachis, in the same manner, just as is 
the case in the Leguminosae. 
The Marattiacese differ from the glabrous Ophioglosseae in that they are 
hirsute, but not nearly so much so as the true Ferns. 
Fig. 292.—^ under surface of the upper part of a leaflet of Angiopteris cmidata, with sori s s. B some teeth of the margin of 
the leaf Marattia sp. with sori s s. C half a sorus with opened sporangia (chambers). 
The Sporangia of the Marattiacese are developed in considerable number on 
the underside of ordinary leaves which have undergone no further modification. 
Like those of the majority of true Ferns they are borne upon the veins of the 
leaves, and are usually arranged in two rows forming sori, which either cover the 
veins running from the midrib to the margin of the leaflet throughout their whole 
length {Dancßd), or only for a short distance near the margin {^Angiopteris, Marattid) ; 
in Kaulfussia they are placed upon the delicate anastomosing branches of the 
veins. The sorus is borne upon a cushion-like outgrowth of the tissue of the 
vein, the placenta. In Angiopteris alone are the individual sporangia free from 
each other; they are ovoid and sessile, and when mature they open by a lon- 
gitudinal slit on their internal surface. If the sporangia of each row of the 
sorus be imagined to have become coherent, and the two rows to have become 
attached by their adjacent surfaces or to have completely coalesced, a structure 
results which actually occurs in Marattia (Fig. 292, C). This structure might 
well be regarded as a sporangium with numerous chambers arranged in two rows 
