304 ON SEEDLINGS 



trichomanefolium. Here they are oblong, incipiently emargin- 

 ate, cordate at the base, asymmetrical, entire at the sides, or 

 with a deep incision on one or both sides at or below the 

 middle, usually very unequal at the base, fleshy, glandular- 

 pubescent above and on the petioles. E. moschatum agrees 

 with this, and E. cicutarium merely differs in being perhaps 

 more deeply lobed with one or two incisions on each side. E. 

 Manescavi merely differs in being very shallowly crenate along 

 the sides. Pelargonium australe (fig. -229) is comparable to 

 the last in being shallowly crenate at the sides, but is sub- 

 lobate at the base. The fission, toothing, or lobing seems to 

 be intended to facilitate folding in the seed. It will be noticed 

 that the fission is always most pronounced towards the base 

 where the cotyledons are broadest, and that the lobes are 

 directed towards the narrower apex, so that by this means the 

 greater width at the base is reduced. One large lobe or deep 

 incision would accomplish in this respect what a number of 

 smaller ones would, so that both types answer the same 

 purpose. 



The sixth type is represented by Geranium, the difference 

 between which and Erodium has perhaps reference to the fact 

 that while the seeds of Erodium are arranged so as to be self- 

 sowing, and terminate in a sharp point, which more readily 

 pierces the ground, this is not the case in Geranium, the 

 seeds of which are rounded at both ends. The different 

 species, as far as my observations go, agree in the relatively 

 large size of the cotyledons, and the amount of folding which 

 they undergo in the seed. They differ chiefly in size and 

 vigour, and in the relative length of the hypocotyl and the 

 petioles of the cotyledons. G. Wallichianum (fig. 228) may 

 be taken as a representative of seedlings with a short hypocotyl 

 and long petioles. The cotyledons are obliquely reniform, 

 asymmetrical, deeply cordate at the base, shallowly sinuate at 

 the apex, with the midrib excurrent, forming a small tooth, 

 five-nerved, thinly pubescent above, ciliate at the margin, 

 equalling one another in size, but the two halves of each un- 

 equal. The average length of the longer half of five cotyledons 

 is 12-8 mm. and the width 8-6 mm. ; on the contrary the 

 average length of the shorter half is 11-5 mm. and the width 



