846 REPORT— 1901. 



Idnds bearing numerous vegetative buds. The sporangia are scattered on the under 

 side of tbe fertile leaves, and have no true indusium, Tbs roots in the mature 

 plant arise from the bases of tbe petioles. 



The vascular bundles in the petiole are arranged in two concentric rings, the 

 outer ring being tbe larger ; each individual bundle has a bi-collateral structure. 



The stem is polystelic, an outer ring of large steles and an inner group of 

 smaller ones being found. The structure of each bundle is bi-collateral. In 

 young stems the steles are all the same size, the bundles of the first leaves and 

 roots of tbe young plant being in close connection with those in the stem. The 

 apex of the stem is in the form of a cone with a three-sided apical cell. 



The roots have a single stele and several air-passages. Tbe latter arise as 

 splits between cells at a short distance below the three-sided apical cell. 



The vegetative buds arise from a single cell. The apical cone is at first very 

 broad, with a three-sided apical cell. In older buds the apex gradually narrows. 



Ceratopteris has more strongly marked affinities with the Polypodiaeese than 

 with any other of the Leptosporaugiate ferns. It has slighter affinities with the 

 Marsiliacefe, and may possibly be intermediate in position between these two 

 orders. 



3. An Apparatus for Studying the Rate of Floiv of Solutions in Plant 

 Stems. By Richard J. Anderson, Af.A., M.D., Professor of Natural 

 History, Queen's College, Galtvay. 



The agents producing tbe circulation of fluids in plants have been regarded as 

 mainly physical. Osmosis, capillarity, tbe removal of the fluid by transpiration, 

 chemical changes in the tissues and fluids, and, if some biological factors be 

 added that work out the details of distribution, the agents are well-nigh cata- 

 logued. Vital force, if one may use the term, and the change from liquid to 

 gas, and the reversing of this process, have failed to explain the rise of fluid 

 in stems to a height of 200 to 300 feet above the earth. It is therefore of 

 interest to study the conditions imder which solutions traverse stems. Two 

 methods of studying tbe laws of transmission naturally suggest themselves. A 

 water-head may be secured by placing a box at a level sufficiently high to secure 

 tbe desired pressure and a portion of tbe stem to be examined connected by a 

 suitable tube to the reservoir; or, imitating the force of transpiration, a suction 

 force set up by means of an aspirating reservoir may be employed. I have used 

 the following method : A rod four feet long is fixed at its centre to a rotating 

 axis. The axis is caused to revolve by a motor (electric preferably). Two stems, 

 as nearly alike as possible, five-eiarhths of an inch in diameier at tbe thickest end 

 and eight inches long, are taken and connected each to two small bottles or tubes 

 by caoutchouc. Each bottle has a tube, or second neck, leading to tbe outer air 

 to maintain the pressure uniform in the bottles. The tube at the stem pole of one 

 of the specimens to be examined and that at the root pole of the other are to be 

 three-quarters filled with weak solution of vellow prussiate of potassium in each 

 case, or a solution of eosin. A solution of perchloride of iron can be used to test 

 the stems in the former case. The two stem specimens are now to be fixed to 

 each side of tbe rod with the bottles containing the fluids nearest the centre and 

 at the same distance. An axial reservoir may be substituted for the two inner 

 bottles. This has been completed, but I have not yet used it. Stems of ^sculus, 

 Syringa, and Philadelphus have been employed. Solutions pass freely througb 

 stems of Syringa, if the bark be retained, when the rod moves at tbe rate of ninety 

 revolutions per minute. In some experiments the flow from the radical to the 

 apical pole seemed freer. The fluid passed much less freely after removal of the 

 bark. These statements are only provisional. Tbe following interesting ques- 

 tions arise : («) The rate of flow in diflerent stems ; {b) the comparison of the 

 flow from tbe radical pole of one stem with the flow from the apical pole of 

 another ; (c) tbe comparison of the conducting power of the barked stem with 

 the stem in which tbe bark is intact ; {d) tbe conducting powers of tbe different 



