278 



OX SEEDLINGS 



Endosperm plentiful, like a transparent jelly, occupying all the 

 interior of the unoccupied space in the growing seed and surround- 

 ing the embryo, ultimately becoming dry and cartilaginous, occupying 

 the space between the folds and wrinkles of the mature embryo, 

 and still transparent where quite thin, mucilaginous and swelling up 

 considerably when placed in water. 



Embryo quite straight at first and lying in the conical hollow 

 process near the hilum which forms a passage for the radicle to the 

 micropyle ; but later on as growth proceeds the cotyledons are pro- 

 jected beyond this process and commence to become concave towards 

 the inner angle of the seed. They soon become doubled sharply 

 over the end of the process, extending to the apex of the seed and 

 both doubling over and abutting against the prominent ingrowth of 

 the tegmen, become deeply bifid at the apex, more or less cordate at 

 the base, and much wrinkled. 



Ipomoea Quamoclit, L. (fig. 539). 



Ovary of two carpels, two-celled or by the interposition of 

 spurious septa four - celled ; 

 ovules as in I. Pes-caprae. 

 Fruit a capsule. 

 Seed trigonous, flat on the 

 sides in contact with the others, 

 rounded on the dorsal aspect 

 both longitudinally and trans- 

 versely, deep brown almost 

 black, pubescent ; hilum small, 

 brown, facing the placenta ob- 

 liquely ; tegmen invaginated 

 rather deeply but squeezed down 

 by the growing embryo, so that 

 in cross-section it resembles the 

 letter J. 



Endosperm in the mature 

 seed forming a layer surround- 

 ing the embryo, subtransparent, 



FIG. 539. Ipomeea Quamoclit, x 13. 

 Seed laid open, showing the dorsal face of 

 the embryo in situ : I, invagination of 

 the tegmen; oc, testa, and ic, tegmen 

 of seed; a, auricles of cotyledons; B, 

 radicle. 



when 



becoming mucilaginous 

 placed in water. 



Embryo large, conduplicate 

 and curved, pale yellowish ; 



cotyledons large, foliaceous, bifid, cordate at the base, bent back at 

 the end of the invagination of the micropyle and doubled in beneath 

 it, then recurved upwards and proceeding to the apex of the seed ; 

 radicle subfusiform or cylindrical, obtuse, curved towards the 



