SAXIFRAGES 



505 



glutinosum. The primary or leading ovate form is still pre- 

 served, but the cotyledons are rather distinctly five-nerved. 

 Of the former the first two leaves are trifid, while succeeding 

 ones are more or less deeply five-lobed. The cotyledons of 

 E. nigrum are oblong, and the first two leaves are cuneate 

 or lanceolate, often shallowly trifid ; the ultimate form is 

 palmately five-lobed and five-nerved. 



The variety E. nigrum laciniatum has similar but much 

 smaller cotyledons. A well-marked modification of this type 

 occurs in Philadelphus gracilis (fig. 828) with broadly ovate 

 and emarginate cotyledons. The first two leaves are ovate 

 and entire, whereas the next two are serrulate. 



Rodgersia podophylla, A. Gray (fig. 326). 



Primary root slender, tapering downwards, flexuose, giving off 

 slender lateral rootlets. 



Hypocotyl undeveloped or indistin- 

 guishable from the root. 



Cotyledons ovate, obtuse, entire, 

 shortly petiolate, with a distinct midrib, 

 glabrous, light green ; lamina 1 '5-2-25 

 mm. long, T25-2 mm. wide ; petiole 

 grooved above, convex on the back, 

 dilated at the base and connate, forming 

 a little cup around the plumule, about 

 1 mm. long. 



Stem herbaceous, producing under- 

 ground a stout, scaly rhizome, and throw- 

 ing up a stem when about to flower ; 

 primary internodes undeveloped. 



Leaves simple, trilobed on the stem, 

 five-sect on the rhizome, alternate, 

 stipulate, petiolate, palmatinerved at the 

 base in the seedling, alternately nerved 

 upwards, palmately or peltately nerved 

 in the adult leaves, glabrous or nearly so 

 in tbe seedling stage ; petioles semiterete, 



channelled above, more or less hairy, short in tbe seedling, very long 

 on the rhizome of the adult plant, dilated and sheatbing at the 

 base ; stipules membranous, attached to tbe petiole, fringed at the 

 apex in tbe seedling stage. 



FIG. 326. 

 Rodgersia podophylla, x 8. 



