XLVIl] 



MONOGRAMME— ANTROPHYUM 



241 



MoNOGRAMME Schkuhr 



This genus includes depauperate examples of the same type of structure 

 as Vittaria. Clathrate scales and spicular cells are abundant: but the thin 

 rhizome, which forks occasionally, is protostelic, the simple leaf-traces coming 

 off alternately from the margins of the slightly flattened stelar strap. The 

 venation of the narrow, grass-like leaves is greatly simplified: it consists 

 only of a mid-rib with an occasional lateral vein, right or left, that dies out 

 often without fusion. The sporangia are of the Vittaria-ty^^, with paraphyses: 

 but the spore-counts give the lower typical numbers of 32 to 48, suggesting 

 a derivative state. 



ANTROPHYUM Kaulfuss 



This genus also has simple leaves, but they are of firm and fleshy texture, 

 with copious hexagonal areolae. Spicular cells and paraphyses are as before. 



Fig. 74 1. Reconstructed vascular systems. A = oi Antrophyuin lineatiim, showing 

 the dorsiventral dictyostele with two closely inserted nodes. B = o{ Anetium citri- 

 folium, with one node, and one internode. (After Williams.) 



The anatomy shows a gutter-shaped dictyostele, with alternate leaf-gaps on 

 its upper side, which overlap: sometimes there may be a closed solenostele 

 {A. plantagineinn (Cav.) Klf ). From the base of each leaf-gap arise the binary 

 traces (Fig. 741, A). These widen out, and branch as they pass into the 

 blade, with or without a distinct mid-rib being formed. The sori, which are 

 Bin _ 16 



