Development of Sporangium in Schizaea rupestris: contributions from the Hull Botanical Laboratory 398

1. All the tissues of the root have their origin in a pyramidal apical cell. 2. The root structure is probably the simplest of all observed roots. 3. Tissues of the root are differentiated extremely early; the initials of the epidermis, cortex, endodermis, and pericycle are only one cell removed from the apical cell. 4. The inner cortical layer and endodermis have a common origin; both are cortical. 5. The pericycle and desmogen strand have a common origin; both are stelar. 6. The arrangement of the bundle is diarch, consisting of four or six xylem cells and from eight to twelve phloem cells. 7. Thickening of the inner and radial walls of the "sclerotic layer" is a striking feature. 8. Epidermal cell of root hair destiny can be recognized very close to the apical region, and root hairs persist throughout the life of the root. 9. Histological distinction is unreliable as a guide to adult tissues.