1 54 Parkin . — Histology of Monocotyledons. 
EXPLANATION OF FIGURES IN PLATE XIII. 
Illustrating Mr. Parkin’s paper on the histology of Monocotyledons. 
Figs, i— 1 2 taken from sections, cut from spirit-material and mounted in alcohol, 
so as to retain the mucilage in the cells. Drawn under a Reichert No. 5, objective. 
Funkia ovata — petiole. 
Fig. 1. Transverse section of a raphide-cell. 
Fig. 2. Longitudinal section of the same : r. bundle of raphides ; m. mucilage 
precipitated by alcohol. 
Fig. 3. Transverse section of a crystal-sac with mucilage. 
Fig. 4. Longitudinal section of the same : c. bundle of acicular crystals ; 
n. nucleus ; p. protoplasm. 
Phormium tenax var. atropurpurea — leaf. 
Fig. 5. Transverse section of a crystal-sac without mucilage. 
Fig. 6. Longitudinal section of the same. 
Fig. 7. Transverse section of a crystal-sac with two crystals : c. solitary crystal. 
Polianthes tuber osa — tuber. 
Fig. 8. Transverse section of a crystal-sac without mucilage. 
Fig. 9. Longitudinal section of the same. 
Fig. 10. Longitudinal section of a raphide-cell : r. bundle of raphides ; c. bundle 
of acicular crystals ; n. nucleus ; p. protoplasm. 
Tritoma Uvaria — root-stock. 
Fig. 11. Transverse section of a crystal-sac. 
Fig. 12. Longitudinal section of the same: c. bundle of crystals; n. nucleus; 
p. protoplasm. 
Narcissus poeticus — foliage leaf- base. 
Fig. 13 (natural size). Line a-b shows the position of the absciss-layer; l. upper 
leaf ; s. bulb scale. 
Fig. 14. Semi-diagrammatic longitudinal section through region marked c-d in 
Fig. 13. The absciss-layer in process of formation is shown by the zone of narrow 
cells recently formed with conspicuous nuclei : v. vessel ; r, raphide-cell ; the 
lumens of both being obliterated by the pressure of the dividing cells ; oe. outer or 
lower, ie. inner or upper epidermis. 
