24 
EQUISETACE.®. 
‘ On the Reproductive Organs of Equisetum, by Mr. Joseph Heii” 
derson,’ published in the Linnean Transactions.* Fig. a repre- 
sents a detached spore, with its investing cell or integument ; the 
little appendage at either end is supposed to be the remains of 
what connected it with contiguous cells when lying in the theca 
at an earlier stage : h shows the indistinct commencement of the 
sutures of the integument, which subsequently separates at these 
sutures : c c, the same still further advanced, exhibiting all the 
sutures of the integument : c? is an end view, showing the dilated 
extremities of the tw^o linear portions, into which the integument 
is about to divide ; the central figure [e) exhibits the spiral linear 
divisions of the integument after separation ; f the spore with 
its outer tunic, after immersion in dilute tincture of iodine.— 
These purely microscopic parts are most probably unavailable 
as affording characters for discriminating species ; I have intro- 
duced them merely to give an idea of the inexhaustible fund 
of instruction contained in every part of these interesting plants. 
Transactions of the Linnean Society of London, vol. xviii. p. 567, pi. 39. 
