438 OX SEEDLINGS 



obtuse. The cotyledons of Rheum officinale (fig. 622) are 

 broadly ovate, obtuse, obscurely three- to five-nerved, and 

 have their petioles slightly connate at the base. The hypo- 

 cotyl is undeveloped or indistinguishable from the root, which 

 becomes thick and fleshy at an early stage. The first leaf is 

 ovate-oblong, subcordate at the base. The ultimate leaf is 

 cordate-palmate, five-nerved and -lobed, and lobulate or 

 coarsely dentate between the lobes. 



A very distinct type is met with in Coccoloba uvifera 

 (fig. 623) which has cotyledons similar to those of Coffea. 

 They are large, foliaceous, oblate or subquadrate, five-nerved 

 from the base, strongly reticulate, and truncate at the apex 

 or widely, shallowly and erosely emarginate. 



The large and foliaceous cotyledons of Fagopyrum are also 

 very distinct. They are more or less unsymmetrical with 

 unequal basal auricles as explained above. Those of F. 

 emarginatum are rhomboid-orbicular, unsymmetrical, five- 

 nerved at the base and penninerved upwards. The first leaf 

 is cordate-hastate, and the second similar but more acu- 

 minate, with ochreate stipules as in other members of the Order. 

 The cotyledons of F. tataricum (fig. 620) are suborbicular, 

 rounded at the apex, and very unequally auricled at the base 

 with the larger auricle of one on the opposite side from that 

 of the other as it was developed in the seed. The venation is 

 similar to that of the last species. 



Pterostegia drymarioides, Fisch. et Mey. 



Primary root slender, flexuose, finely branched. 



Hypocotyl short, subterranean and scarcely distinguishable from 

 tlie root, red. 



Cotyledons rotund, obtuse, entire, petiolate, glabrous; lamina 

 6-5-7-5 mm. long, and about the same in width ; petiole slender, 

 slightly furrowed on the upper surface, 9-11 mm. long. 



Stem herbaceous, dichotomously branched ; 1st internode unde- 

 veloped ; 2nd 5-9 mm. long. 



Leaves simple, radical and cauline, opposite, unequal, stipulate, 

 petiolate, very thinly pubescent or almost glabrous ; petiole slen- 

 der, slightly channelled above. Inequality of leaves ; lamina 6'5- 

 7'5 mm. long and 1-1-3 cm. wide ; petioles 1-7-2 cm. 



Stipules represented by a slender connecting rim between the 

 petioles or by their slightly connate bases. 



