EXPLANATION OF PLATE XXI. 
Fic. la. Section from Demonelix showing fossilized root remains. Two small rootlets with 
root-hairs, h, grew into the cavity formed by the decomposition of a larger root. 7, bundle sheath 
enclosing the outer portion of the vascular bundle. x 65. (Kighth ring from bottom, Demon- 
elix 17. Harrison Beds, Sioux Co., Nebraska.) 
Fic. 16. Cross-section of rootlet as usually found in Demonelix. Only the epidermal and 
cortical tissues are preserved. x 65. (Transverse section of Demonelix cake (late Miocene). 
Upper Monroe Creek Beds, Sioux Co., Neb.) 
Fic. 2. Longitudinal section of rootlet showing epidermal tissue and, /, root-hairs. x 65. 
lod 
(Section from Ring 4, Demoneliz 17. Taken close to the surface of specimen.) 
Fie. 3. Cross-section of rootlet showing the stele or vascular bundle, s, and sand grains, p. 
x 65. (From the interior of Ring 8, Demonelia 17.) 
Fig. 4. Cross-section of central portion of root showing the bundle sheath, c, with vascular 
tissue inside and cortical tissue outside. x 65. (Ring 12, Pamenelia 17.) 
Fic. 5. Longitudinal section of root showing the methcd of branching. x 31. s, stele. 
(Longisection of Deemonelix “cake” from near its edge (late Miocene), Upper Monroe Creek 
Beds, Sioux Co., Neb.) 
Fie. 6. Section taken longitudinally and including a bend in the root. s, stele. x 50. 
(Section taken parallel to the surface of “ rhizome’? of Damonelix 17. Harrison Beds, Sioux Co., 
Neb.) 
Fig. 7. Portion of same showing part of the stele at a greater magnification. w, tracheary 
vessels or wood cells. x 275. 
Fra. 8. Portion of same stele still more enlarged. ¢, cortical cells; 6, bundle sheath ; «, 
reticulated wood vessel. x 400. 
Fic. 9. Section from fragment of an older root showing a regular superimposition of the 
cortical celis, ce. x 65. 
Fic. 10. Cross-section in same fragment showing, w, woody tissue and, ¢, cortex. x 65. 
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