678 
PROFESSOR F. O. BOWER ON PHYLLOGLOSSl/M DRUMMONDII, 
PLATE 72. 
Fig. 24. A more advanced plant, showing, in addition to the parts seen in fig. 23, a 
new tuber (t 2 ), and two roots (r). ( X 20.) 
Fig. 25. A plant germinated about five weeks, showing the same parts as fig. 24. 
c — sporangium-bearing cone. (X5.) 
Fig. 26. A mature plant, showing the arrangement of parts. /=leaves, r= roots, 
£;=old tuber, £ 2 =new tuber, a =sporangium-bearing axis. (x3.) 
Fig. 27. A mature plant with similar parts, with the addition of the supernumerary 
leaf (l). 
Fig. 28. Median longitudinal section of a new tuber in its first stage of development, 
compare fig. 15. The depression of the surface at (a) is already apparent. 
(X 175.) 
Fig. 29. A similar section through an older tuber ; the depression at a is deej>er, and 
the channel above it is already beginning to be closed up. (X 175.) 
Fig. 30. A similar section through a still older tuber; the channel is here completely 
closed. (x325.) 
Fig. 31. An older tuber drawn under low power (20) to show its general outline. 
Fig. 32. Apex of a similar tuber, with the completely closed channel. (X 325.) 
Fig. 33. Opening of the channel of same tuber as fig. 32, at the external surface. 
(X 130.) 
Fig. 34. Median longitudinal section of a root in early stage of development. Compare 
fig. 16. (X 175.) 
PLATE 73. 
Fig. 35. A rather older root. The periclinal divisions in superficial cells are very 
regular. (xl75.) 
Fig. 36. Transverse section of a mature leaf. ( X 130.) 
Fig. 37. Median longitudinal section of a mature leaf. ( X 130.) 
Fig. 38. Two elements from a longitudinal section of the mature leaf. (x325.) 
Fig. 39. Central part of a transverse section of a mature peduncle, n — intercellular 
spaces in the xylem. ( X 175.) 
Fig. 40. Part of a transverse section of the base of the leaf, showing peg-like pro¬ 
jections into the intercellular spaces. (X 325.) 
Fig. 41. Part of a transverse section of a root, showing the vascular tissue, surrounded 
by an ill-defined bundle sheath ( b . sh.). 
Fig. 42 a, b, vascular systems of two plants bearing no sporangia. 1, l, bundles from 
leaves, t, bundle running to tuber, r, bundle running to root. 
Fig. 43 a, b, vascular systems of sporangium-bearing plants, ax =bundle running 
down the stem. 
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