CH. XXV] 



HABIT 



It is in point of fact a very perfect example of a catadromic helicoid dicho- 

 podium: even the middle lobe, which often appears to hold a terminal 

 position, has been recognised as the inner branch of the second dichotomy 

 (see Vol. i, Fig. 82 A, which is a much reduced photograph of a leaf). The 

 segments themselves are pinnatifid, and the solitary sori are borne on their 

 wings at points near to the midrib. Another species, M. sarmentosa, found 

 strictly localised at Sarawak, Borneo, has dichotomous rhizomes, and 

 straggling pendent leaves. At first sight the branching of its leaves appears 

 quite different from that of M.pectinata: but this is due partly to the unequal 

 development of the dichotomies, certain of the branches being represented 

 only by arrested buds: partly it is due to their sympodial development: but 

 still the dichopodial branching appears to hold for both. The branching in 

 M. sarmentosa as worked out by Prof. Compton {New Phyt. viii, p. 204, 

 1909) is readily related to a primitive dichotomous type. The rachis forks 



Fig. 497. Matouia, portions of leaf, to show the venation and vascular 

 connections of sori. a, Matonia sarmentosa. b, M. pectiiiata. (After 

 Diels.) c, J/. /tfc/wrt/fl, sterile region. (After Seward.) 



repeatedly: either both branches may develope equally, and elongate, forkino- 

 again and again: or one of the branches may develope fully while the other 

 after bearing a few pinnae ends in an aborted bud. The latter is the more 

 usual, as is seen in Diels' illustration (Engler and Prantl, i. 4, Fig. 183). In 

 both species the venation is dichotomous, and mostly free (Fig. 497), but in 

 M.pectinata there are vein-fusions (<;), and especially about the insertion of 

 the sori {It), though even these are absent in the more attenuated M. sar- 

 mentosa {a\ The sori of the former species are large, and are seated solitary 

 on a plexus of veins : those of J/, saruicntosa are smaller, and more 

 numerous, forming a row on either side of the midrib, as in Gleichenia. In 

 both of these closely related species there is an overarching indusium formed 

 from the apex of the receptacle. 



The dermal appendages of the genus are simple hairs, often thin-walled 

 at the base, but with the acute tip indurated ; in fact they have the same 

 structure and appearance as those of Gleichenia pectinata, but without any 

 basal emergence. 



