XI THE HOMOSPOROUS LEPTOSPORANGIAT.-E 371 



and a filament is first formed, after which the flat prothalHum 

 grows for a time by a single apical cell, which is finally replaced 

 by a group of marginal cells. In Aneiinia and AloJiria the 

 growing point lies on one side, so that the prothallium is not 

 heart-shaped. In Lygodiuiii} however, the prothallium has the 

 ordinary form. 



The development of the antheridia has been studied by 

 Kny -' in Aneiviia Jiirta. The only difference between this and 

 the normal antheridium of the Polypodiacese is that in Aneiniia 

 the first wall is always flat instead of funnel-shaped, and the 

 basal cell of the antheridium is therefore disc-shaped. The 

 archegonia appear to correspond exactly with those of the 

 Polypodiacese. 



The tissues of the sporophyte in Lygodiiini and Schtzcea are 

 much like those of GleicJienia and the Hymenophyllacese. As 

 in these the stem is traversed by a single concentric vascular 

 bundle, as well as the petioles. In Aneiviia and MoJiria the 

 bundles of the stem form a cylindrical network like that of the 

 Polypodiacea;. The stem bundles are concentric, as are those 

 of the petiole and larger veins in all but Schiscea, which Prantl ^ 

 states has collateral bundles throughout, except in the stem. 

 The small veins have collateral bundles as in other Ferns. 

 Sclerenchyma is largely developed, especiall)^ in the petioles, 

 where the whole mass of ground tissue in Lygodiiini (Fig. 192) 

 is composed of this tissue. 



The leaves are pinnate in all the forms except a few species 

 of Sc/iizcsa. Lygodiiini, as is well known, shows a continuous 

 growth at the apex of the leaf, something like Glcidienia, 

 but here the primary apex retains its meristematic condition, and 

 the extremely long and slender axis of the leaf twines about its 

 support like the stem of many climbing plants. The sporo- 

 phylls are usually smaller than the sterile leaves, or where only 

 portions of the leaf are sporiferous these are much contracted. 

 The anatomy of the leaf corresponds closely with that of the 

 other Ferns. The stomata, which are for the most part con- 

 fined to the lower side of the leaf, are always arranged in two 

 parallel rows in Schiscea, and the peculiar stomata of Aneiniia 

 have already been mentioned. The trichomes are for the most 

 part hairs. Only in 2LoJiria do scales occur. 



The leaves arise from the upper side of the creeping stem, 



1 Bauke, Bot. Zeit. 1878. ]_"- Kny (4). •■ Prantl (5), p. 23. 



