84 7. GLEICHENIA. § 3. MERTENSIA. 



1. Fronds membranaceous to subcoriaceous, not rigid. 



» Under surface not glaucous or pruinose., and if so, then greenish 

 or bluish. 



Forma typica: Ultimate segments subcoriaceous, under 4 cm. long, 

 entire, or emarginate at the apex; under surface naked or provided with 

 deciduous, more or less crisped hairs on the costulae and veins. 



Forma tenera: Ultimate segments membranaceous. 



fa.!*, nialayaiia: Very large, with the branches much elongated; 

 ultimate segments 4 cm. or more long. 



*• Under surface glaucous or pruinose, pntrplish. 



War. tetrapliylla: Accessory and geminate branches nearly 

 equal, relatively short and broad, to 12 cm. long by 7 cm. broad. 

 ±.±. Fronds chartaceous or coriaceous, not rarely rigid. 



S. Fronds very irregularly dichotomous. 



War. alter uans: Branches with the internodations geniculate 

 or flexuose and bearing at or near the nodes alternate, simply pinnatifld 

 branches and opposite or subopposite to these a branch provided vsdth 

 an axillary bud and not rarely elongated and grown out again to an 

 irregularly dichotomous branch; costae not acutely 2-marginate above; 

 ultimate segments chartaceous or subchartaceous, beneath glaucous or 

 pruinose, and deciduously ferrugineo-pilose on the costulae. 



"far. irreg;ularis : Like var. alternans but the ultimate segments 

 beneath not glaucous, copiously, though deciduously, provided with crisped, 

 ferrugineous hairs on the costulae and veins. 



War. inaeffualifs: Like var. alternans but with one of each 

 pair of fork-branches often oppressed and the accessory branches wanting 

 or rudimentary; costae acutely 2-marginate above; ultimate segments 

 beneath densely ferrugineo-tomentose. 



S.3. Fronds regidarly dichotomous. 



3. Ultimate segments distinctly glaucous or pruinose beneath. 



War. nornaalis : Fronds chartaceous, beneath naked or sparingly 

 tomentose. 



3.3. Ultimcde segments not distinctly glaucous or ^wuinose beneath. 

 4L. Veins beneath not sulcate (impressed) neither dark-coloured ; 

 under surface soon naked. 



War. rigida: Fronds rather small, up to 40 cm. each way, once 

 to thrice forked ; ultimate segments oblong or linear-oblong, obtuse, subbullate, 

 very hard and rigid; veins indistinct or somewhat prominent beneath. 



