154 ON SEEDLINGS 



showing the venation only by transmitted light, petiolate ; lamina 

 10-15 mm. long, 10-12 mm. wide (the rotund forms being the 

 wider) ; petiole flattened above, convex beneath, dilated and connate 

 at the base. 



Inequality of cotyledons. In plant No. 1, 2'5 and 2'75 cm. ; in 

 plant No. 2, T75 and 1'5 cm. long. 



Stem herbaceous, developed when about to flower ; primary 

 internodes undeveloped. 



Leaves simple, radical and cauline, alternate, exstipulate, petio- 

 late, alternately, ascendingly incurvinerved, the reticulate venation 

 seen best by transmitted light, rather coarsely hairy all over, deep or 

 light green ; petioles channelled above, convex beneath, hairy, stout^ 

 tapering upwards from a broad, slightly clasping base ; hairs hyaline, 

 simple or forked, or with a small lateral branch. 



Nos. 1-3. Varying from oblong to oval, or broadly ovate, 

 rounded and obtuse at the apex, suddenly tapered at the base, slightly 

 dentate, with the teeth tipped with a yellowish glandular mucro ; 

 the nerves incurved and uniting with one another within the margin, 

 forming a series of large reticulations. 



Hesperis nivea, Baumg. 



Primary root tapering downwards, with many lateral rootlets. 



Hypocotyl terete or tapering downwards, 5-6 mm. long, greenish 

 above, colourless below the soil. 



Cotyledons oval-oblong, obtuse, entire, indistinctly one-veined ; 

 petioles broad, channelled on the upper surface. 



Stem as in H. matronalis. 



First leaves entire or slightly serrate ; first two broadly sub- 

 rotund, obtuse, the rest broadly oblong, all covered with rather stiff 

 hairs, indistinctly pinnatinerved ; petioles broad, much longer than 

 the leaves, hairy, rather deeply channelled on the upper surface. 



Hesperis bituminosa, Sam. 



Hypocotyl 2-3 mm. above the soil. 



Cotyledons roundly obovate, more or less unequal, measuring 

 11 and 13-5 mm. respectively, and in another case 12 and 13 mm., 

 glabrous except the slightly channelled petioles, blunt or very 

 shallowly emarginate. 



First leaves ovate, obtuse, slightly dentate, but sometimes more 

 elongated and spathulate, hairy. 



Sisymbrium officinale, L. 



Siliqua linear or subterete, somewhat compressed, short, erect, and 

 closely adpressed to the stem ; the numerous seeds mostly in one row. 



