158 Boeshore — The Morphological Continuity 0} 



or rounded tuber from three-fourths to an inch and a half long. 

 The writer considers the upper part of the tuber as the stem axis 

 which bears the tooth-like scale-leaves. In some specimens the 

 stem part consists of more than half of the tuber, in others of 

 less than half. The scales are shorter, but more numerous than 

 those of Aphyllon. Stomata are present on the scales, and 

 along the scale-edge a few multicellular hairs were seen. Ad- 

 ventitious roots arise from the surface of the stem. 



Histological details have been worked out by Cooke and 

 Schively and the writer has found his own investigations to agree 

 with their descriptions. But by way of comparison of this genus 

 with preceding genera some of these details will bear repetition. 

 The most notable feature is the bundle system, which becomes 

 broken up into separate bundles that have no definite arrange- 

 ment in rings, thus giving the stem a more loose and open as- 

 pect. This is an advance in degradation from Aphyllon in 

 which the bundles, though separated, form a fairly definite ring 

 about the pith. The phloem greatly exceeds the xylem, a fur- 

 ther advance in degradation with increased parasitic habit. To 

 quote shortly from Cooke and Schively: "The phloem of a 

 bundle .... shows a tendency to spread out and lie in 

 separate patches, while the xylem of each bundle seems always 

 concentrated in a single area. Many of the bundles show an in- 

 ternal duplication with reversed order, phloem, xylem, xylem, 

 phloem, succeeding each other from without inwards . 

 An internal phloem is almost always present, often in excess of 

 the outer phloem mass." No such state of affairs as the last 

 exists in Aphyllon. As a consequence of the scattered and 

 elongated bundles the cortex and pith areas have become re- 

 duced in size. 



Sections of the floral axis have been described by others. The 

 bundles are arranged in a ring. Considerable hard bast is de- 

 veloped. Hairs and stomata constitute the epidermal growths, 

 the former showing considerable reduction in size as compared 

 with the hairs on the floral axis of Aphyllon. 



No definite statement will be ventured as to how much of the 

 plant constitutes the stem axis in Conopholis (Plate XVI, Fig. 

 32). The aerial portion in its lower part is densely covered with 

 scales that may represent reduced and degraded leaves, while 

 slightly above this point the scales become more distinct, sep- 



