248 
Jeffrey and Torrey . — Transitional Herbaceous Dicotyledons . 
EXPLANATION OF PLATES XI-XIIL 
Illustrating Messrs. Jeffrey and Torrey’s paper on Transitional Herbaceous Dicotyledons. 
... 
PLATE XI. 
Fig. 1. Transverse section of a year-old stem of the common Linden ( Tilia ) in the region of 
a node, showing the absence of foliar rays such as are characteristic of woody herbs. 
Fig. 2. Foliar segment of Fig. 1, more highly magnified to show the woody character of the |; 
tissues subtending the foliar trace. 
Fig. 3. Tangential section of the foliar ray of the woody herb Abutilon . 
Fig. 4. Tangential section of the foliar segment in Tilia , showing the absence of the foliar ray 1 
in this genus. 
Fig. 5. Entire transverse section of the stem of Abutilon sp. , showing clearly the presence of j|; 
three foliar rays, corresponding to the three foliar traces on the margin of the pith. 
Fig. 6. One of the foliar rays of Abutilon in transverse section, more highly magnified than ! 
Fig. 5. Compare this with the transverse section of Tilia in Fig. 2. 
Fig. 7. Transverse section through part of the nodal region of the woody cylinder of Tilia sp., ; 
showing the foliar gap which interrupts the continuity of the wood internally to the leaf-trace. 
Fig. 8. Transverse section of the foliar ray of Oenothera biennis , taken from the aerial region of ) 
the stem. 
Fig. 9. Transverse section of the entire axis of Hibiscus syriacus in the region of the node. 
On the right is seen a foliar ray extending through three annual rings. 
Fig. 10. Transverse section of part of the foliar ray shown in the preceding figure. The ray is | 
seen to be made up of normal wood rays and of fibres, but vessels are conspicuous by their absence. 
Fig. 11. Total transverse section of the slender region of the aerial axis of Boehmeria nivea in 
the region of the node. 
Fig. 12. Part of the same more highly magnified to show the nature of the foliar rays in the 
slender region of the stem. 
PLATE XII. 
Fig. 13. Transverse section of the nodal region of a year-old stem of the American Elm ( TJlmus | 
americana ) to show the absence of foliar rays in an Urticaceous woody axis. 
Fig. 14. A foliar segment of Ulmus americana , and its internally subtending foliar trace. The 
absence of modification in the woody structure of the leaf-segment is very obvious. 
Fig. 15. Entire transverse section of the nodal region of the stem of Boehmeria nivea , a woody 
herb of Urticaceous affinities, showing, in contrast to Fig. 13, the obvious presence of foliar rays in 
relation to the foliar traces. 
Fig. 16. One of the foliar rays of Boehmeria nivea in transverse section. It is subtended 
internally by its corresponding foliar trace. 
Fig. 17. Transverse section of the foliar gap of Boehmeria nivea. The leaf-trace subtends it 
externally in the cortex. 
Fig. 18. Tangential section of the foliar ray of Boehmeria nivea. 
Fig. 19. Part of the same, more highly magnified. 
Fig. 20. Total transverse section of the aerial perennial stem of Xanthorhiza, showing numerous 
foliar rays and their corresponding foliar traces. 
Fig. 21. Part of a transverse section of the same species, more highly magnified to show three 
foliar rays extending through three annual rings and subtended by their corresponding foliar traces. 
Fig. 22. Tangential section of two foliar rays of Xanthorhiza 
Fig. 23. Transverse section of Euphorbia Cyparissias , showing a clear alternation of numerous | 
stem bundles and of foliar rays subtended by their foliar traces. 
Fig. 24. Transverse section of leaf-segment of Robinia Pseudacacia , showing the absence of 
a foliar ray. 
Fig. 25. Transverse section of the foliar ray in the woody herb Melilotus alba. 
