Observations on the Vascular System of Ferns. 113 



and connected with the poles of a battery by the separate wires 

 and cups {p n.) The centre of this box is open to admit the 

 shaft of the magnet, as is also the centre of the box (e.) This 

 box is made of two glass cylindrical sections, cemented into a 

 groove of a tm-ned cup or base of wood. It contains two cells 

 for mercury nearly semicircular, and Insulated from each other 

 precisely as the cells for the Ritchie magnet. These cells are 

 connected with the extremities of the spiral by the separate wires 

 and cups {a h.) The two wires (z z) are well insulated by a 

 winding of varnished silk, and secured in their positions on the 

 shaft by silk thread. The upper extremities of these wires dip 

 into the concentric cells of (^,) and the lower into the cells 

 of box (e.) The base board is made thin, and the pivot {g) 

 short, to allow the magnet to come as near as possible to the 

 spiral. Place the instrument upon the spiral, make the connex- 

 ions as above directed, and the magnet immediately commences 

 a rapid rotation by the influence of the spiral. The instrument 

 should always be placed without the centre of the spiral, and in 

 such a manner, that the insulating pieces between the cells of 

 (e) should be in the direction of a radius of the spiral. 



Art. VIII. — Ohservatio7is on the Vascular System of Ferns ^ and 

 Notice of a motistrous flower of Orchis spectahilis ; by J. W. 

 Bailey, Professor of Chemistry, Mineralogy and Geology, at 

 the U. S. Military Academy, West Point. 



I. On the Vascular System of Ferns. 



It is a question of much interest in vegetable anatomy, whether 

 spiral vessels exist in ferns ; for if they do, ferns present a remark- 

 able deviation from the usual structure of flowerless plants. It 

 is well known, that the presence or absence of these vessels has 

 been considered so invariably connected with the presence or ab- 

 sence of flowers, as to have given rise to the division of the vege- 

 table kingdom into the two great classes Yasculares or Flower- 

 ing, and Cellulares or Flowerless Plants. Ferns are by all writers 

 placed in the last class, but it will be seen by the following quo- 

 tations, that there exists much uncertainty with regard to their 

 having spiral vessels. 



Vol. XXXV.— No. 1. 15 



