TILIA 



53 



space, they would become extremely thick. In endospermic 

 seeds this would present no difficulty, as the additional space 

 would be simply filled by endosperm. In Lepidium, however, 

 this device cannot be resorted to ; but the two lobes just fill 

 up the vacancy. 



In the Lime (Tilia) (fig. 101) we have another very interest- 

 ing case. 



The cotyledons are broad, foliaceous, rhomboid-subtri- 

 angular, and 5-lobed, 5-nerved at the base, with the outer 

 and lower pair of nerves 

 slender, alternately nerved 

 upwards, reticulate, shin- 

 ing and thinly pubescent 

 on both surfaces, deep 

 green above, paler be- 

 neath, petiolate ; lobes ob- 

 long-obtuse, with a strong 

 nerve running into each, 

 the outer ones always 

 largest and sometimes 

 ovate ; middle pair of lobes 

 always the smallest, and 

 oblong or subulate ; lamina 

 15-21 mm. long, 17-25 

 mm. from tip to tip of 

 the basal pair of lobes; 

 petiole semiterete, shal- 

 lowly channelled above, 

 pubescent, 6-8 mm. 

 long. 



The fruit is an ovoid 



or subglobose nut, with five obtuse angles, tomentose with 

 somewhat rufous hairs, one-celled by the rupture of the 

 septa, one-seeded, indehiscent, tipped with the persistent 

 base of the style, woody, and attached to a large deciduous 

 bract which serves to disseminate it by the aid of the wind. 



The seed is ascending or erect, obovoid or subglobose, deep 

 brown, smooth, with a firm or crustaceous testa of two distinct 

 layers ; hilum oval, comparatively large on the ventral aspect 



PIG. 101. Tilia vulgaris. Seedling. 

 Nat. size. 



