3 1 6 
Notes . 
orthostichies, Z. complanaium , Linn., having four, but all those 
examined (viz. Z. carolinianum , Linn., Z. Wigblianum, Wall., Z. com- 
planatum , Linn., Z. scariosum , Forst.) appeared to differ from the 
Selaginella- type either in leaf-arrangement or in the number of 
orthostichies. 
The structure of the stem of Z. volubile was examined to see 
whether the distichous habit was connected with any modification 
in the structure of the stele, but this was not found to be the case. 
The larger stems have a perfectly normal Lycopodium- structure, with 
several xylem-bands, separated from one another by phloem, and 
bearing peripheral protoxylem-groups. The stele shows reduction 
in its size and complexity at each successive branching, just as may 
be seen in a species of Lycopodium with radially placed leaves. In 
branches of four successive orders the protoxylem-groups numbered 
seventeen, fourteen, eight and seven respectively. Some of the xylem- 
bands are free; others fused. They are generally straight, and lie 
in the plane of branching of the stem, which is also the plane of the 
large leaves in the distichous region. In the latter region there are 
mostly only two xylem-bands fused at one end, and bearing seven or 
eight very prominent protoxylem-groups. It may be mentioned here 
that the mature sporangium in Z. volubile is axillary in position, and 
has a well-marked stalk, as in Z. Selago , Linn. 1 
Z. salakense , Treub, is not one of the dimorphic species, but has 
small, sparse, adpressed leaves on its stem, and crowded leaves on 
its branchlets in eight orthostichies or sometimes in whorls of five 
at the apices 2 . It is mentioned here because it differs from other 
species of Lycopodium in the structure of its stem. The xylem of the 
stele does not form well-marked bands, but the tracheides are arranged 
in small groups and curved uniseriate rows, mostly rounded off, and 
separated from one another by a network or labyrinth of phloem. 
The structure has consequently a deceptive resemblance to that of 
a Gleichenia. In the larger branches the protoxylem-groups also are 
unusual, in that they are very broad tangentially, so that they have 
the appearance of a nearly continuous peripheral band, which is 
interrupted at intervals by peripheral groups of phloem. The phloem 
is thus sometimes completely shut in by xylem for considerable 
distances. The above structure appears to belong to the type of 
1 Bower, Morphol. of Spore-producing Members, Phil. Trans. 1894, p. 511. 
2 Treub, Ann. Jard. Bot. de Buitenzorg. vii. p. 141. 
