Mr. Brown on an undescribed Fossil Fruit. 471 
stinctly shows, in the arrangement of its vascular bundles, a preparation for 
the supply of an equal number of bractez. These vascular fasciculi are 
nearly equidistant in a tissue of moderately elongated cells. 
The vessels are exclusively scalariform, very closely resembling those of the 
recent Ferns and Lycopodiacee ; and among fossils, those of Psarolites, Lepi- 
dodendron, and its supposed fruit, Lepidostrobus, as well as several other fossil 
genera; namely, Sigillaria, Stigmaria, Ulodendron, Halonia? and Diploxylon. 
The coat of the sporangium appears to be double; the outer layer being 
densely cellular and opake, the inner less dense, of a lighter colour, and formed 
of cells but slightly elongated. 
On the lower or adnate side of the sporangium this inner layer seems to be 
continued, in some cases at least, in irregular processes to a considerable 
depth. I cannot, however, find that the sporules are actually formed in this 
tissue, but in another of somewhat different appearance and form, of which 
I have only been able to see the torn remains. 
The minute granular bodies which accompany the sporules in the drawing 
Tas. XXIV. fig. G. are probably particles of the mother cells, and are neither 
uniform in size nor outline. 
The whole specimen has suffered considerable decay or loss of substance, 
which is most obvious in the sporangia from their greater transparency, but 
equally exists in the opake bractez, in which radiating crystallization occu- 
pies the space of the removed cellular substance. 
I cannot at present enter fully into the question of the affinities of Triplo- 
sporite. I may remark, however, that in its scalariform vessels it agrees with 
all the fossil genera supposed to be Acotyledonous. In the structure of its 
sporangia and sporules it approaches most nearly, among recent uive, to 
Lycopodiacee and Ophioglosseæ ; and among fossils, no doubt, to Lepidostro- 
bus, and consequently to Lepidodendron. 
The stem structure of Lepidodendron, known to me only in one species, 
Lepidodendron Harcourtii, offers no objection to this view, the vascular ar- 
rangement of the axis of its stem bearing a considerable — to that 
of Triplosporite. To the argument derived from an agreement in structure 
between axis of stem and of strobilus I attach considerable importance, an 
equal agreement existing both in recent and fossil Conifere. 
VOL. XX. 3Q 
