GENERAL MORPHOLOGY 291 
straggling or creeping forms these may arise adventitiously at points far 
up along the axis. It is by comparison as regards the differences which 
occur in this otherwise uniform family that some knowledge of the course 
of development of the Lycopod-type may be derived. 
The Lycopodiales are divided, according to the presence or absence 
of a ligule, into two divisions; the Eligulatae, which include the Lycopo- 
diaceae, that is the living genera Lycopodium and Phylloglossum, with which 
are also to be associated certain early fossils designated Lycopodites; and 
NZ, ZZ 
A- 
Shoots of several species ot Lycopodium to show the form and arrangement of the 
leaves. A=L. rufescens, Hook. x2. B=L. mandioccanunt, Raddi. Natural size. 
C=L. reflexum, Lam. X2. D=L.casuarinoides, Spring. : part of a terminal branch of 
an old plant. x4. BH=L. cernuum, lL. x2. = ZL. volubile, Forst, seen from above. 
x2. (From Engler and Prantl.) 
the Ligulatae, which include the Selaginellaceae and Isoetaceae of living 
forms, together with the fossil Lepidodendraceae and Sigillariaceae. These 
will be severally considered as illustrating variants on the simple strobiloid 
type of the whole phylum. 
A. ELIGULATAE. 
The genus Lycopodium, which includes about a hundred living species, 
was arranged by Spring according to the degree of differentiation of the 
several species.1 He distinguished two main sections of the genus, the 
first including those with sporangia scattered over the length of the shoot : 
the second including those with the sporangia associated in definite cones. 
The former section was again sub-divided according as the leaves were 
all alike, or as a distinction appeared between sterile and fertile leaves: 
the latter section according as the shoot was developed radially or 
dorsiventrally. The details of Spring’s scheme have since been modified, 
but the principle remains the same in the classifications of the present 
day: it is to arrange the genus along lines which clearly indicate a 
progressive differentiation and specialisation of sterile and fertile tracts. Such 
an arrangement naturally harmonises with evolutionary theory. The species 
1 Monographie des Lycopodiacées, 1841. 
