﻿On Palm Trees. 



179 



toward the right, makes an angle with the axis of the stem of 38° ; the 

 helix ascending toward the left, an angle of 25° with the central axis. 



In the palmetto, the angle ABC, is 70°, the angle ABD, 37°. (See 

 Figure 2.) 



Desfontaines showed that the vascular bundles which run to the leaves, 

 come from the centre of the stem, in the date palm, and in monocotyledons. 

 Decandolle adopted this theory, while Molenhauer declared positively 

 against its being a truthful conclusion. 



One thing is certain ; we find the leaf-bud starting at the very apex of 

 the central axis of the cylindrical stem, and the matured leaf finds its 

 final resting place on the exterior of the trunk, and on the ascending 

 helix — the vascular fibres which run to the petiole of the leaf must neces- 

 sarily be bent from the centre of the cylinder to the circumference, in order 

 to adapt themselves to the movements of the growing leaf. Von Mohl 

 states that the bundles of vascular tissue start from the periphery of the 

 trunk, incline very gradually toward the central axis, then, by a marked 

 curvature turn outward — toward the leaf stems. Thus it occurs in trac- 

 ing the bundles upward. 



"The vital or milk vessels for sap In the vascular bundles run from the 

 periphery toward the central axis of the stem, thence to the leaf. The 

 'proper vessels' convey clear sap, and lie isolated in the interspaces of the 

 cellular tissue, in the vicinity of the vascular bundles in the pith. The 

 milk vessels, or vital sap vessels, exist independently, each set of vessels 

 conveying wholly different sap." 



Speaking of the two kind of vessels for conveying sap in monocotyledons, 

 Von Mohl says, "These vessels (the milk vessels) then, are distinguished 

 from the proper vessels (vasa propria) in the vascular bundles, by their 

 different situation and by the red color of their contents, which color is 

 never assumed by the sap of the proper vessels. 



"The proper vessels in the vascular bundles of Sagittaria are no less 

 clearly distinguished from the milk vessels lying scattered in the 

 parenchyma of the peduncle and petiole, for the latter convey milky sap ; 

 the former very transparent sap." 



I can not conclude without inviting the attention of our citizeDS to the 

 necessity of a Botanic Grarden in Cincinnati. I have not time to dilate 

 upon its vital importance in connection with the pursuits of medicine, 

 agriculture, horticulture, dyeing and weaving — or in inventing patterns 

 for textile fabrics, and for the decorative arts. 



The Moors, who excelled in their colors and arabesques, established 

 magnificent gardens on their first entry into Spain. 



