I 



* 



i 



1902] ON THE DEVELOPMENT OF CERTAIN PIPERACEAE 339 



tissue (including epidermis); cp^, middle layer of carpellary tissue ; cp^, inner 

 layer of the same ; em, embryo ; es, embryo sac ; espy endosperm ; espn, endo- 

 sperm nucleus; hy, hydathode ; iin, inner integument ; />?, integument ; vtp, 

 micropyle ; nc, nucellus ; o, ovum or egg ; oc, oil-containing cell ; oin, outer 

 integument ; osp, oospore ; phi, plumule ; p7t. polar nucleus; ps, pollen sac ; 

 pspy perisperm ; rh, roothair; s^, synergid ; st, stigma; sta, stamen; sto, 

 stoma ; tp, tapetal cells ; vb^ vascular bundle tissue. 



All figures are camera drawings, and all are from microtome sections 

 exceptyf^5. /,j7,andj'9. 



Figs, i-iS- Piper medium Jacq. 



Fig. r. Superior view of young flower; the stigmas are often three in 

 number, X 30. 



Fig. 2, Tranverse section of an ovary slightly younger than that shown 

 i^T^^- 5» showing indications of the three constituent carpels. X 50, 



Fig. 3, Longitudinal section of ovule at the beginning of formation of 

 integuments. X 360. 

 * Fig. 4. Similar section after the formation of tapetum. X 360, 



Fig. 5. Longitudinal section of ovary when integuments have just closed 

 in at the micropyle. X 50. 



Fig. 6. Longitudinal section of ovule from such an ovary, X 360. 



Fig. 7. Longitudinal section of a nucellus containing a four-nucleate 

 embryo sac. X 360. 



Fig. 8. Similar section at a slightly later stage. X 360. 

 ' Fig. g. A similar section of an eight-nucleate embryo sac. X 360. 



• Fig. 10, Longitudinal section of a ripe embryo sac; the nuclei of the 



synergids from the adjoining section shown in dotted lines. X 360. 



Fig. II. Longitudinal section of a nearly full grown fruit. X 30. 



Fig. 12. Detail of micropylar region of same, with embryo sac showing 

 multinucleate non-cellular endosperm. X 360. 



Fig, 13. Longitudinal section of somewhat older embryo sac, and adjoin- 

 ing portions of nucellus, showing peripheral layer of cellular endosperm ; the 

 synergids indicated in dotted lines are from the adjoining section. X 175. 



Fig. 14. Longitudinal section of ripe food and seed, showing relative 

 development of embryo, endosperm, and perisperm. X 30. 



Fig. 15, Transverse section at about the middle of ripe fruit. X 30- 



Figs. i6~ji, Heckeria twibellaia L, 



Fig. 16. Part of longitudinal section of spike, passing through three 

 ovaries and their subtending bracts. X 360. 



Fig. 17. Longitudinal section of an older ovary and the enclosed ovule. 



X 175- 



Fig, 1 8. Longitudinal section of still older ovule showing tapetum. X 360. 

 Fig. ig. Longitudinal section of still older ovule. X 360. 



