1897 | STAMENS AND CARPELS OF TYPHA LATIFOLIA Io! 
Fic 21. Tetrad with one-celled microspores with very thick walls. Xx 
1200. 
Fic. 22. Irregular pollen tetrad. X 1200. 
F1G. 23. Nearly mature pollen tetrad. X 1200. 
Fic. 24. Two pollen grains showing circular germinating pores. X 1200. 
Fic. 25. Pollen grain before shedding, showing the generative cell and 
tube nucleus. X 1200. _ 
Fic. 26. The same. X 1200. 
Fic. 27. Outline of cross section of stem showing the origin of the carpels. 
x 135. 
Fig. 28. Longitudinal section of young carpel. X 650. 
FIG. 29. Longitudinal section of young carpel, showing epidermal origin 
of the hairs which are produced in acropetal succession. X 1200. 
F1G. 30. Section of carpel a li:tle older. X 1200. 
Fig. 31. Section of carpel showing the annular zone which gives rise to 
the ovary cavity. X I200 
F1G. 32. Section of carpel just before the appearance of the nucellus 
X 780. 
G. 33. Section of carpel showing the origin of the nucellus with one 
archesporial cell. x 1200. 
FIG. 34. Section of carpel a littleolder. x 420. 
Fic. 35. Nucellus with primary tapetal cell and sua aah mother cell 
X 2250. 
Fic. 36. Section of carpel. x 200. 
Fig. 37. Nucellus, showing the primary tapetal cell divided into two 
X 2250. 
Fig. 38. Section of nucellus, showing a long axial row back of the macro- 
Spore mother cell. * 1200 
Plate VI. 
FIG. 39. Section of nucellus, showing origin of the integuments. X 2250. 
FIG. 40. Section of nucellus a little older than fig. 38. X 1200. 
Fig. 41. Section of nucellus, showing the macrospore mother cell devel- 
oping dete into the fertile macrospore. X 2250. 
FIG. 42. Section of nucellus showing disorganization of the two tapetal 
cells. X 2250. 
Fic. 43. Section of nucellus, showing further disorganization of the tape- 
tal cells. x 2250. 
