PLATE XVIII. 



Koeberlinia spinosa. 



Fig. 1. Cross section of stem. P, pith; M, medullary ray; W, wood; 

 Tr, tracheal tubes of year '07 (?) ; Fh, phloem; Sa, spongy pa- 

 renchyma air space; Pa, palisade air space; Ea, epidermal air space; 

 B, bast; Scl, sclerenchymatous tissue. Semi-diagrammatic, x 25. 



Fig. 2. (a) Section from an older stem, showing traces of annual rings, 

 '07, '05. (6) Portion of same stem, opposite side, showing '06 trace. 

 Semi-diagrammatic, x 25. 



Fig. 3. Cross section of flower branch, showing region of wa, water 

 storage cells. X 283. 



Fig. 4. (a) Pith from flower branch, showing air spaces, A. Cross, 

 X 283. (6) Single cell from flower-branch pith, showing pits, P; 

 air spaces, A. Cross, x 400. 



Fig. 5. Pith of old stem, showing pitted conditions and starch bodies. 

 Cross, X 283. 



Fig. 6. Crystals in old pith cells; longitudinal section. X 283. 



Fig. 7. Diagrammatic representation of regions of older stem. E, epi- 

 dermis; P, palisade; Sp, sponge; B, bast; S, stone cells; Ph, phloem; 

 W, wood. Enlarged. 



