ANATOMY OF THE GENUS SALICORNIA. 345 
4. The flowering spike is constructed on the same plan as the vegetative 
shoot, but the internodal bract-sheath is necessarily modified on account of 
the two groups of flowers which develop at the node. 
5. Leaf-fall occurs in both the annual and perennial species. It is due to 
the suberisation of the cells of the outer layers of the stem tissues, beginning 
in the endodermis and extending inwards, this results in the death of the 
internodal foliar tissue and its subsequent separation at the limit between 
the stem and leaf. | 
6. The seedling has two small, fleshy cotyledons and a short thick hypo- 
cotyl. The cotyledons fuse and form a cotyledonary sheath to the hypocotyl 
similar to the leaf-sheath of the vegetative shoot. The hypocotylar sheath 
has an outer series of bundles derived from the two cotyledonary traces. 
Transition from stem to root structure takes place high up in the hypocotyl 
and follows Van Tieghem’s Type III. 
7. The morphology of Aalidium joliatum and Haloenemum strobilaceum 
further indicates how the Salicornian condition may have arisen. 
8. The discovery of every form of transitional element between spiral 
cells and stereides leads to the conclusion that the two are homologous 
structures ; the former function chiefly in water storage, the latter in 
mechanical support. 
9, Anomalous secondary growth sets in early in both root and stem, A 
secondary, pericyclic cambium gives rise on its inner margin to a thick zone 
of lignified intermediate tissue, in which concentric series of collateral 
vascular bundles are embedded. 
10. At the base of the main stem, the upper part of the main root, and 
the rhizome of the perennial species, the secondary cambium forms an 
aerating cortex of greater or less extent. In Salicornia herbacea it develops 
into a thick coating of aerenchyma, and ribs of this tissue oceur in 
S. ramosissima. 
11. Halocnemum strobilaceum has long and short shoots. The long shoots 
are covered with decussately arranged, fleshy leaf-buds, which latter develop 
into the short shoots. The long shoots are old “short shoots” from which 
the foliar sheath has fallen leaving the buds exposed. The jointed segments 
of the short shoots are similar to those of Salicornia. The anatomy of the 
free leaves of the bud and the foliar sheath of the segment is essentially 
similar, and agrees in all important points with that of Salicornia glauca, but 
stereides are absent from the palisade parenchyma, and the foliar bundles of 
both the tree leaves and the sheath are associated with numerous transfusion 
tracheids. 
