EXPLANATION OF PLATES 111 
Fics. 11-18. Richardsonia pilosa 
FiG. 11. Nucel 
Fic, 12. Ovule in TA sac cell. The strophiole is seen. 
Fic. 13. Embryo-sac 
Fic, 14. Embryo-sac eid small antipoda 
Fic. 15. An antipodal cell as it appears aem the cell wall is secreted. 
Fic. 16. Ovule with endosperm and embryo. 
E 17. Embryo of Fig. 16 in detail. 
G. 18. Older embryo and the special cells of the endosperm. 
PLATE 14. Houstonia 
Lettering : 5, stylar primordia; 7, placental primordia; 7, roof element of ovarial 
partition; 4, basal element of ovarial partition; ff, plane of cell division adding to the 
unicle; 2, antipodal cells 
Fic. 1. Æ. coerulea. Longitudinal section through a young flower. 
Fic. 2. 24. longifolia. Longitudinal section through an older flower. 
Fic. 3. Æ. longifolia. A similar section after the fusion of the basal and roof 
partitions. 
Fic. 4. A nucellus with a single functional megaspore mother-cell, 
Fic. 5. Archesporium, showing two smaller megaspore mother-cells which do not 
divide. The arrow indicates the direction of the egg pole. 
. 6. Two megaspores formed, and the second daughter-cell in division. 
IG. 7. Embryo-sac with tw 
IG. 8. Ovule in which the tires contains four nuclei in telophase 
Fic. 9. A. coerulea. Definitive embryo-sac. At the antipodal pole there are two 
megaspore mother-cells still persistent 
Fic. 10. Z. coerulea. Ovule with three-celled embryo, and endosperm. 
Fic. ۰ One esili: embryo. 
Fic, 12. Five-celled embryo. 
PLATE 15 
. Conductive epidermis ( Diodia Virginiana) in young ee in the re- 
gion x fasion pisc: the roof and basal elements of the ovarial 
Fr A portion of the stylar conductive tissue penetrated pis T ten tubes. 
Portods d three such tubes are shown. 
Fic, 3. A portion of the stylar tissue showing a pollen tube taking a brief course 
xui a large E with the longitudinal axes of the cell (Richardsonia pilosa). 
G. 4. Pollen tubes as seen in the base of the stylar tissue, turning to pass into 
the - Priser tissue ( Æ. pilosa 
Fic. 5. Mouth of micropyle and adiacent conductive tissue, with a pollen tube 
(R: pilosa). 
Fics. 6, 7. Ovular conductive tissue of the kind seen in fig. 5, cut transversely to 
the er axes of the cells. Parts of pollen tubes are seen passing between the 
cells er 
"P Conii epidermis of Diodia Virginiana. 
Fie 9. A small portion of the surface of e conductive epidermis of Diodia 
Virginiana showing the pollen tube on the su 
Fics, 10, 11. Parts of pollen tube pos س‎ plugs (Diodia Virginiana). 
