118 THE MARATTIALES 



and the character of the reproductive organs are marked indications of the primitive 

 nature of these ancient ferns. The embryo also shows many points in common with 

 that of the Ophioglossaceae. As in the latter, the organs of the young sporophyte 

 are all of epibasal origin and the vascular system in the young sporophyte belongs 

 exclusively to the leaf and root, the stem being entirely destitute of a proper stele. 



In DancBo a short suspensor is usually developed, but the other genera have as 

 yet shown no examples of this. 



The sporophyte is very much alike in its early development in all of the Marat- 

 tiaceae. The young plant consists at first mainly of the primary leaf and root, which 

 are traversed by a single axial vascular strand as in Ophioglossum moluccanum, but 

 a stem apex is developed at an early period, although it remains relatively incon- 

 spicuous. 



Kaulfussia, Dancea, and Archangiopteris are all ferns of moderate size and 

 comparatively simple structure ; but Marrattia, Angiopteris, and Macroglossum 

 are very large, and the arrangement of the vascular bundles in the stem becomes 

 exceedingly complex, corresponding to the numerous bundles in the enormously 

 developed leaves. 



The form of the leaf in the Marattiaceae ranges from a perfectly simple leaf in 

 Dancea si m pit ci foil a to the gigantic decompound leaves o{ Angiopteris and Marattia. 

 Most of the species oi Danaa (and this is true also oi Archangiopteris and Macro- 

 glossum) have simply pinnate leaves, while in Kaulfussia the leaves are palmately 

 divided into from three to seven leaflets, the larger leaves looking curiously like a 

 horse-chestnut leaf in outline, whence the specific name. The ternate form, which 

 is often found in Kaulfussia, recurs in the early leaves of the other genera and is 

 sometimes retained in quite large leaves in Marattia (plate 12, B). This recurrence 

 of the ternate leaf form suggests Helminthostachys and the ternate species of 

 Botrychium. The leaves are usually quite smooth, but in the earlier stages there is 

 sometimes a sparing development of hairs and scales. The latter are especially 

 noticeable upon the leaves of the young sporophyte in Dancea. 



The leaves are furnished at the base with very conspicuous fleshy stipules 

 which remain adhering to the stem after the leaves fall away, and these leaf bases, 

 with their attached stipules, more or less completely cover the surface of the stem. 

 As the leaves fall away they leave a characteristic scar marked by the remains of the 

 vascular bundles. The leaf base as well as the stalks of the leaflets shows a more or 

 less marked enlargement, recalling the pulvinus which occurs so commonly in the 

 Leguminosae. It is at this point that the leaf stalk separates, the smaller divisions 

 of the leaf often breaking away from the main or secondary rachis, in the same 

 fashion as the main leaf stalk falls. In the large species of Marattia and Angiop- 

 teris this enlatjged leaf base with the two thick, fleshy stipules curiously resembles 

 in shape and size the hoof of a horse. 



The leaves when young are coiled up in the same fashion as those of the typical 

 ferns and their venation in general is decidedly fern-like, the ultimate veins being 

 dichotomously branched and the venation very much like that of Helminthostachys 

 or certain species of Botrychium. In Kaulfussia, however, the venation is reticulate 

 and strikingly like that of the typical Dicotyledons. In its earlier stages, however, 

 there is a marked resemblance to the venation of Ophioglossum. 



The fleshy leaves do not, as a rule, show a very large development of mechanical 

 tissues; but there is developed, especially in the larger leaves, a thick layer of hypo- 

 dermal tissue, which is usually sclerenchyma, somewhat like that of the typical ferns, 

 but may be thick-angled tissue or coUenchyma, such as is common in many flow- 

 ering plants. A marked anatomical feature is the presence of large mucilage ducts. 



