for petioles, which when full grown are about 1-2 cm. long. 

 Geranium Wallichianum (fig. 228), G. polyanthus and Pelar- 

 gonium australe (fig. 229) afford other good instances in this 

 Order, and Delphinium elatum, already mentioned in Kanuncu- 

 lacese, is also a case where petioles are required to carry up 

 the lamina of the cotyledons to the light. 



A fourth type is represented by Tropseolum majus (fig. 231). 

 Here the cotyledons are subterranean even after germination, 

 large, fleshy, filling the testa, and shortly petiolate, so as to 

 facilitate the exit of the plumule. 



The seed then lies on one side of the seedling, and the 

 hypocotyl is undeveloped as in the case of other seedlings with 

 subterranean cotyledons. In this respect T. aduncum, T. 

 minus, and other species agree with the type just given. 



The fifth type is represented by Erodium and Pelargonium, 

 which have broadly ovate-oblong or suborbicular cotyledons, 

 generally distinctly narrowed towards the apex. This type 

 varies exceedingly however indifferent species, from cotyledons 

 of nearly equal or symmetrical form to others that are strongly 

 asymmetrical, while in a third modification they are lobed or 

 pinnatifid. The least complicated type may be represented 

 by Pelargonium bipinnatifidum, which has broadly oblong or 

 oval, finely pubescent cotyledons, rounded or faintly emarginate 

 at the apex, and cordate at the base, but otherwise entire, with 

 rather long slender petioles, and a symmetrical lamina. P. 

 humifusum agrees with the last, while P. vitifolium has sub- 

 orbicular but otherwise similar cotyledons. A more generally 

 typical form occurs in Erodium verbenae folium, in which the 

 cotyledons are broadly ovate-oblong, emarginate, unequally 

 cordate at the base, where they are five-nerved, penninerved 

 upwards, unsymmetrical, glandular, ciliate, and glandular- 

 pubescent beneath. The auricle on one side is about 1 mm. 

 longer than the other, a circumstance due to its being on the 

 outside of the coil of the seed, where it has more room to 

 develop. The channelled petioles are also of unequal length, 

 in the proportion of 8'75 to 5*25 mm. E. gruinum and E. 

 malacoides have altogether larger cotyledons, more deeply 

 emarginate and more asymmetrical, but otherwise similar to 

 the last. Lobed cotyledons are represented by Erodium 



