PLATE XXII. 



Koeberlinia spinosa. 



Fig. 1. Portion of palisade P, and spongy parenchyma, Sp, tissue, from 

 stone cells to epidermis. Numerous intercellular spaces /. S., are 

 found. Cross section, x 283. 



Fig. 2. End view of palisade cells, showing number and size of chlo- 

 rophyll bodies. Tangential section, x 283. 



Fig. 3. Epidermis of young stem, showing large cellular space, cs, and 

 thin walls; this also shows frequency of deeply sunken stomata, ss. 

 Cross, X 283. 



Fig. 4. Portions of older epidermis, showing reduction of cell space by 

 intense cutinization ; cell space, cs; cutinized portion, cp. Cross, 

 X 283. 



Fig. 5. Tangential view of older epidermal cells, showing thickening of 

 walls. X 283. 



Fig. 6. Single stoma from young stem, showing large guard cells, Gc. 

 Also, small stomatal chamber proper, above and below, sc. Cross, 

 X 283. 



Fig. 7. Outer stomatal chamber invaded by phycomycete. Ph. Cross, 

 X 283. 



Fig. 8. Stomatal apparatus. OA, outermost aperture; E, epidermal cell 

 space; osc, outer stomatal air chamber; isc, inner stomatal air cham- 

 ber; Pr, projection of thickening, making stomatal spaces proper, 

 ssp; P, palisade cells; AS, air space in sponge. Cross, X 283. 



Fig. 9. Outline of regions of aerating spaces, showing frequency of 

 spaces. E, epidermal region; p, palisade region; s, sponge region. 

 Enlarged. 



