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about to close the leaf-gap. Then it separates again and passes 
slowly across the central ground-tissue to the next leaf-trace above. 
Gwynne-Vaughan found the internal strand, traced downwards, 
ending blindly in the pith in one place, so that just below that point 
the dictyostelic cylinder alone was present (Fig. 71, A). The roots 
Fig. 71. Archangiopteris Ilenryi. Transverse sections of stem, si., stele ; 
1.1., leaf trace ; internal accessory strand. From Gwynne-Vaughan. 
Fig. 72. Archangioplerts Henryi. Transverse sections of petiole and 
rachis. The dotted line indicates the general leaf-trace curve. The small 
arrow attached to each strand shows the position of the (endarch) proto- 
xylem. A.— Pulvinus. The thin lines with arrows indicate the course of the 
internal strands. B.—Pulvinus. C, D,—Petiole. E.— Rachis just below 
the insertion of a pinna. From Gwynne-Vaughan, 
