Sporangium-bearing Organs of the Lycopodiaceae. 57 
really axillary, is of course a proliferated axillary bud, and it is 
perhaps interesting to compare it with a bulbil of L. selago, though 
such analogies cannot have any morphological value. 
VI. — Summary of Results. 
I. The sporophylls of the different species of Lycopodium can 
be arranged in a continuous series, increasing in complexity of 
structure. In the simplest forms, such as L. selago , the sporangium 
is almost completely exposed, whilst in L. cernuum, the most highly 
differentiated species, the sporophyll has a dorsal flap, and affords 
perfect protection to the sporangium. 
II. In L. cernuum, and nearly allied species, the adult 
sporangium arises from the sporophyll stalk; but in all the simple 
forms it is found in the axil of the sessile sporophyll. In inter¬ 
mediate cases, such as L. inundatum and L. carolinianum, the sporo¬ 
phyll is stalked, but the sporangium is axillary. Even in L. selago, 
however, the young sporangium is not differentiated from leaf- 
tissue, but is formed from the axis of the cone itself. 
III. No definite vascular bundle supplies the sporangium 
pedicel, but in it are often found elongated cells with more or less 
lignified walls. These are very simple in some species (L. serratum, 
Phylloglossum, etc.), very highly specialised in others ( L . volubile, 
L. inundatum, L. cernuum, etc.), but they are never directly con¬ 
nected with the sporophyll trace, though in L. volubile they were 
found to be in continuity with the layer of cells with lignified walls 
which surrounds the trace. 
IV. Our present knowledge of the relations of the Lycopods, 
both amongst themselves and with fossil genera, appears to be 
insufficient to determine certainly which way we shall read the 
above series, that is, whether we consider the simpler Lycopods to 
be primitive or reduced. Evidence, based on embryology and the 
structure of the gametophyte, tends to support the latter view; it 
is also easier to find connections between the more complex 
members of the series and fossil genera. The series itself is far 
more naturally regarded as a reduction series, and the intermediate 
forms are then far more easily explained. The sporophylls of 
Phylloglossum are found to be comparable with those of some of the 
intermediate species, and it seems probable that this genus repre¬ 
sents a reduced form, as has been recently decided by Bower, 
