THE LIFE OP A SEED. 
403 
loped embryo, not to dilate on the peculiarities of special seeds, 
nor on the varied circumstances which produce deviations from 
the customary course of things in the great majority of seedlings. 
We have, we trust, said enough to show how full of interest for 
observers of very varied tastes and capacities, are the pheno- 
mena connected with the life of the seed, while the intrinsic 
importance of the subject is shown, not only by the peculiarities 
of the embryo plant, and its mode of germination being made 
the chief distinguishing features of the various groups of plants, 
but also because on the due performance of these functions 
we are dependent for our daily bread, in a far wider sense than 
the words in their literal acceptation would imply. 
EXPLANATION OF PLATE. 
Figs. 1 and 2. Ovules of Passiflora from a bud about' half a millimetre 
long. 
Fig. 3. Portion of the placenta from the same flower, showing'ovules in 
various stages of development. 
„ 4. Ovule in process of formation, showing a central nucleus and two 
coverings. 
,, 5. Top-view of No. 4. 
„ 6. Fully developed ovule. 
„ 7. Longitudinal section of the same. 
,, 8. ' Longitudinal section of ovule of (Enothera, showing passage of 
‘ pollen- tube to embryo sac after Tulasne. 
„ 9. Embryo sac of Orchis — early stage. 
,, 10. The same with the germinal vesicles. 
,, 11. The same after contact with the pollen-tube, showing the 
development of the germinal vesicle into the embryo. 
,, 12. Portion of the embryo sac of Iberis after contact with the ger- 
minal vesicle : a suspensor is here formed at one end of which 
' ■ is the embryo. 
„ 13. Further stage in Iberis. 
„ 14. Still further degree of development, showing division into two 
seed-leaves. 
„ 15. Pipe seed of passion flower, the arillus torn. 
„ 16. Vertical section of the same, showing testa albumen and embryo. 
,, 17. Cross section of the same. 
„ 18. Germinating embryo of Galium. 
