4i8 



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 Ophioglosseae. 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 {Angt'opferis) 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 Kaul/ussia. 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. 



-A under surface of the upper part of a leaflet of Angiopteris cciudata, with sori j j. B some teeth of the margin of 

 the leaf of 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 {Danced), or only for a short distance near the margin {^Angiopteris, Marattia) ; 

 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, B, C). This structure might 

 well be regarded as a sporangium with numerous chambers arranged in two rows 



