Lycopodium ccmplanatum and Lycopodium clavatum . 213 
The other plantlet (Fig. 2) is at a much more advanced stage of growth ; 
there is no trace of prothallus visible to the naked eye, but the foot is 
plainly visible as a round warty knob at the base of the stem (ft, PL XXII, 
Fig. 2). The stem has branched several times, and just below the first 
bifurcation is an adventitious root which has already branched three times. 
Numerous leaves clothe the stem ; the upper leaves are green and provided 
with vascular strands, the lower are scale-like. Just above the foot a small 
prominence (p.a. in Pl. XXII, Fig. 2) marks the position of a ‘pseudo- 
adventitious bud, 5 which although of such minute size shows, in a series of 
transverse sections which were made in this region, dichotomy at the apex 
of the stem, and a root has already pushed its way through the cortex, and 
appears as a slight projection at the side of the bud. 
II. Internal Structure. 
A. The Root System. 
(a) First root. The material at hand was not suitable for working out 
the embryonic development of the first root. The investigations of Treub 
and Bruchmann show that the primary root is absent in those forms of 
Lycopodium which they examined. Treub 1 found that in Z. cernuum the 
first root arises in the interior of the embryonic tubercle; Bruchmann 2 
found that in the case of L. clavatum it arises endogenously from the 
hypocotyl, and the latter states that in Lycopodium and Selaginella the 
primary root is rudimentary, and the first functional root is merely one of 
the endogenous lateral roots developed on the embryonic axis. I shall 
use the term first root, therefore, to refer to the first functional root. 
In Z. complanatum the first root comes off laterally, almost at right 
angles to the stem, immediately above the foot region (see r\ PL XXII, 
Figs. 1 and 2). The apex was broken off in both sporophytes I examined, 
but sections nearest the tip show two somewhat bow-shaped groups of 
tracheides with smaller elements at the periphery, usually more or less 
collected at the free ends of the bow (px, PL XXII, Fig. 3) ; between the 
two xylem groups lies a strand of phloem occupying the centre of the 
stele. This agrees in the main with the arrangement described by 
Bruchmann for the first root of Z. clavatum , and with that noted by 
Jones 3 as occurring in a section marked ‘first root’ which was shown to 
him as that of Z. clavatum. Bruchmann calls this a diarch arrangement ; 
Jones says that it may be regarded as diarch or tetrarch. I am inclined 
to think that this arrangement is more correctly described as diarch. 
1 Treub, Annales de Buitenzorg, vol. iv, p. 133, and PI. XVIII. 
2 Bruchmann, Uber die Prothallien und die Keimpflanzen mehrerer europaischer Lycopodien, 
1898, p. 49 and also p. 55. 
3 Jones, loc. cit. , p. 26. 
