Mr. HENDERSON on the Reproductive Organs of Equisetum. 569 
abundance of minute granules. If detached by means of water during the 
globular state, the integument has a flattened appearance (Tas. XXXIX. 
fig. 6.), probably owing to the inability of the membrane to preserve its proper 
form. At Tas. XXXIX. fig. 7. is represented the spore with its membranous 
integument when it has attained sufficient consistency to preserve the oval 
form; it has at each end an appendage of apparently more delicate mem- 
brane, the remains probably of what in an earlier state served to connect the 
contiguous cells. This connecting membrane—if such it be—is the only trace 
of any connexion between one cell or integument and another; it is very soon 
destroyed, and no mark of it remains in a more advanced state of the integu- 
ment. ; 
The next change which the integument undergoes is in the development of 
the spiral sutures, by which it is divided into two narrow bands with broad 
and rounded ends: at first the dividing lines are indistinctly seen traversing 
the integument (Tas. XXXIX. fig. 8.) ; after a time they become more distinct, 
and their spiral direction becomes evident. Two lines of separation run in a 
spiral direction round the integument, and meet in a sinuous transverse suture 
at each end (Tas. XXXIX. fig. 11.) ; these lines cut the integument into two 
equal parts, the ends of which are dilated and uniform; and these are the 
clavate ends of the filaments which have been considered by Hedwig and 
others as forming part of a sexual apparatus. The separation of the integu- 
ment into parts takes place immediately after the edges of the sutures have 
arrived at their proper thickness; it is therefore very difficult after this to find 
the integument entire. 
At Tas. XXXIX. fig. 9. is represented the most perfect which I have been 
able to find after the examination of a great number. The spore at this time 
contains a greenish-coloured fluid mixed with some minute granules; soon 
after it changes to a deeper green colour, its contents become thicker, less 
soluble in water, and filled with a greater number of granules; the fluid 
which had previously filled the integument and the rest of the theca is gradu- 
ally absorbed, leaving the granules which it contained sticking in masses to 
the spores and to the separated portions of the integument. It is these masses 
of granules, when found adhering to the filaments in the ripened state of the 
spore, that have been mistaken for pollen-grains: when removed by means of 
