292 PROTOCYATHEACEAE [CH. xxxii 



GleicJietiia: its area is, however, extended so as to accommodate 50-100 

 sporangia, as against 16 or less. These sporangia have lateral as against 

 median dehiscence, thus removing the need for elbow-room: the stalk also 

 is slightly elongated. All these features, together with the protecting hairs, 

 make an extended sorus with numerous sporangia practically efficient, 

 without loss of spore-output ; for each type of sorus produces about 5000 

 spores {G. pectinata, 256x16=5096; Metaxya, 64 x 100 = 6400). The 

 sporangium of Metaxya is more highly organised than that of LopJiosoria. 

 This is seen in the smaller number of cells of the annulus, its almost vertical 

 position, and in the well-defined stomium of four cells. 



Remembering \h2X Metaxya has been ranked by some of the best authorities 

 as a species of Alsophila, it is well to point again the distinction that while 

 Alsophila has a Gradate sorus, Metaxya is one of the Simplices, its sporangia 

 being simultaneous in origin, as they are also in LopJiosoria. These genera 

 take a synthetic position, linking up the Superficial Simplices and Gradatae, 

 and in particular the Gleicheniaceae, with the Cyatheaceae: they correspond 

 in many features of form, structure, and soral character. But Metaxya also 

 points clearly in the direction of the Matoniaceae and Dipteridaceae, which 

 may be held as probably related to a primitive Gleicheniaceous stock. These 

 aspects of its study seem fully to justify the retention of the substantive 

 genus of Presl with its single living species, Metaxya rostrata Presl. 



PROTO-CYATHEACEAE Bower, 1925 



I. LOPHOSORlA Presl, 1848. ... ... ... I species 



Sorus simple, superficial and naked: receptacle small. 



II. Metaxya Presl, 1836. ... ... ... i species 



Sorus simple, superficial, naked: receptacle flat, of large area. 



BIBLIOGRAPHY FOR CHAPTER XXXII 

 LOPHOSORlA 



550. Sir W. Hooker. Species Filicum. i, p. 47. 1846. 



551. Presl. Die Gefassbiindel iin Stipes der Earn. Prag, 1847, p. 36. 



552. Karsten. Vegetationsorgane der Palmen. 1846, p. 123, PL ix. 



553. Jenman. Synoptical list of the Ferns of Jamaica. Bull. Bot. Dept. of Jamaica, 



1890-1898. 



554. Bower. Origin of a Land Flora. 1908, p. 604, Fig. 336. 



555. Bower. Studiesin Phylogeny. IL Ann. of Bot. xxvi, p. 279. 1912. 



METAXYA 



556. Presl. Tentamen. 1836, p. 59, Tab. i, Fig. 5. 



557. Sir W. Hooker. Genera Filicum. 1913, Tab. xlii, B. 



558. Bower. Studies in Phylogeny. III. Ann. of Bot. xxvii, p. 443. 1913. 



