ANATOMY OF THE ROOTS OF PALMS. 451 
of the relatively main root (Pl. 51. fig. 106). The xylem- and phloem-bundles establish 
connection with several bundles of the parent root. In many cases it was found that an 
incomplete (P1. 51. fig. 106) or complete cylinder of the peripheral system of strands in 
the central cylinder of the root might function as a normal root-cylinder in giving 
rise to lateral roots. 
In Areca Catechu two forms of lateral roots were found (Pl. 51. fig. 111)—the normal 
small roots passing directly outwards, and also roots with much more extensive origin, 
which run obliquely outwards and downwards through the cortex of the parent root, but, 
curiously enough, very seldom reach the periphery, undergoing degeneration during their 
passage outwards; even when they do reach the periphery they usually cease to grow 
and soon abort. The connection of such rootlet with the cylinder of the parent root is 
seen in Pl. 51. fig. 107, where the ruptured endodermis of the main root is shown and its 
connection with that of the lateral root. 
A section taken a short distance above this shows the upward extension of the xylem- 
and phloem-bundles of the lateral root inside the endodermis of the parent root. Here and 
there the phloem-groups of the two are still separate, and in the xylem-groups the 
protoxylem occupies a position between the metaxylem of the main root and the upwardly 
extended xylem of the lateral root. 
The deep penetration of the xylem-elements of the lateral root amongst those of the 
parent root first mentioned by Hugo von Mohl (1) is shown in Pl. 51. fig. 118. The 
protoxylem of the lateral root (pfay. 2) occupies the periphery of the cylinder lying just 
beneath the pericycle, that of the parent root (péry. 1) lying much more internally, 
Elements from the lateral root are seen penetrating centrally as far as, and even beyond, the 
innermost metaxylem-element. The phloem-group shows the small-celled protophlcem 
(ptph.) surrounded by the metaphloem, that lying internally belonging to the main root, that 
externally to the lateral root. Lower down a section shows the cylinders of lateral and 
parent roots quite separate from each other, that of the former being lobed and internally 
composed of separate strands (Pl. 51. fig. 108). More distally the cortex of the lateral root 
is well differentiated, showing the dense outer layers and the parenchymatous inner zone 
with its large air-spaces, the whole being still embedded in the cortex of the parent root 
(Pl. 51. fig. 109). Further down, the cylinder of the lateral root attains a normal 
structure (Pl. 51. fig. 110). 
In Areca concinna these larger internal roots may project for some distance beyond 
the parent root (Pl. 51. fig. 111), but this is apparently an unusual feature. 
Fig. 8. 5 1 a B. 
In Areca concinna a striking peculiarity is shown in the accompanying diagrams 
(text-figs. 8 & 9), where the cylinder of the lateral root in leaving that of the parent 
SECOND SERIES.—BOTANY, VOL. VI. oT 
