346 DICOTYLEDONOTS EMBRYO. 
or less continuous in a straight line with the cotyledons, as in 
the Pansy (jig. 774, 7); if, on the contrary, the embryo is 
curved, the radicle will be curved also (fig. 775), and sometimes 
the curvature is so great that a spiral is formed, as in Bunias 
(fig. 776). In the latter case, where the direction of the coty- 
at fat ledons and radicle is different, 
nets BiG. 4 ae. the latter may form an acute, 
| obtuse, or right angle to them ; 
or be folded back to such an 
extent as to lie parallel to the 
cotyledons, in which case the 
radicle may be either applied to 
their margins, as in the Wall- 
flower (fig. 778, 7), when the coty- 
ledons are said to be accwmbent ; 
or against the back of one of them, 
as in Isatis (fig. 777, 7), when they 
are termed incumbent. 
Fig. 777. Embryo of the Woad Having now described the 
(Isutis tinctoria). 1. Undivided, general characters of the mono- 
2, Horizontal section, ¢. Cotyle- eotyledonous and dicotyledonous 
dons. 7. Radicle-—Fig. 778. : 
Embryo of the Wallflower (Cheir- embryo, we have, in the last place, 
anthus Cheiri). 1. Undivided. 2. to allude briefly to the relation 
See Hee section. 7. Radicle.¢. which the embryo itself bears to 
yledons. 
the other parts of the seed, and 
to the pericarp or cell in which it is placed. 
Relation of the Embryo to the other Parts of the Seed, and to the 
Frwit.—In the first place with regard to the albumen. It must 
necessarily happen that when the albumen is present, the size 
of the embryo will be in the inverse proportion to it ; thus in 
Grasses (fig. 705, a) we have a large deposit of albumen and but 
a small embryo, while in the Nettle (fig. 779) the embryo is large 
and the albumen very small. The embryo may be either external 
to the albumen (figs. 705 and 782), and thus in contact with the 
integuments, as in Grasses, in which case it is described as ew- 
ternal ; or it may be surrounded by the albumen on all sides, 
except on its radicular extremity, as in the Pansy or Heartsease 
(fig. 774), when itis internal. Sometimes the end of the radicle, 
as in the Coniferze, becomes united to the albumen, and can no 
longer be distinguished. 
The embryo is said to be awile or axial when it has the same 
direction as the axis of the seed, as in Heartsease (fiy. 774, pl); 
or when this condition is not complied with, it is abawxile or 
eccentric, as in Rwmex (fig. 780, pl). In the latter case, the 
embryo is frequently altogether on the outside of the albumen, 
and directly below the integuments, as in Mirabilis Jalapa 
(fig. 781, e) and Lychnis (fig. 782, emb), when it is described as 
peripherical. 
We have already observed, that the radicle as a general 
