ANATOMY OF THE ROOTS OF PALMS, 435 
The simplest form in which lignification appears is that of lignified parenchyma. This 
occurs in Latania borbonica, Cocos nucifera, and Acanthoriza australis. The cell-walls 
are thin, and only differ from normal parenchyma in their reactions. In Sabal 
Adansonii the elements are distributed throughout the cortex, and in all specimens of 
Licuala (Pl. 48. fig. 24 & Pl. 49. fig. 28) and Liristona examined they occur in longi- 
tudinal strands. In these genera the walls are thicker and are pitted. 
In Cocos botryophora, Diplothemium maritimum, Bactris minor, and Sabal Palmetto 
(Pl. 49. fig. 33) some of the elements become definite stone-cells in the innermost zone of 
the cortex; and in Cocos plumosa and Caryota urens, a definite zone of stone-cells 
surrounds the endodermis. These elements are first mentioned as occurring in palm-roots 
by Gillain (12). He, however, only gives a short description and does not figure them. 
They are usually thick-walled, deeply pitted, square elements, but they may be quite 
spherical or may be elongated. In Caryota urens the thickening of the walls is so extensive 
that the lumina are almost entirely occluded. 
Quite a different type of element is represented in the fibres so plentifully developed 
in most palm-roots. These are of two distinct types :— 
(a) The Kentia-type. These are long-pointed elements, with comparatively thin and 
more or less pitted walls and large lumina. In some cases transverse walls are present, 
as in Huterpe sp. 
These fibres may occur singly, as in Hyophorbe amaricaulis (Pl. 49. fig. 35), Latania 
Loddigesii, and Huterpe sp., but are much more generally collected into bundles as in 
Kentia (Pl 48. fig. 20 & Pl. 49. fig. 36), Areca Catechu (Pl. 48. fig. 25), and Cyrtostachys 
Renda. In this last species the fibres conform generally to the Kentia-type, but are 
shorter than usual. ; 
(b) The Raphia-type. These fibres are longer, narrower, thicker-walled, and more 
densely provided with simple pits than are those of the Kentia-type. They may occur 
singly, as in Pinanga Kuhlii and Pinanga sp. ; but are nearly always collected into very 
definite bundles traversing the cortex, as in Raphia Hookeri (Pl. 49. fig. 37), all species 
of Phanir examined (Pl. 49. fig. 30), Metrorylon Sagu, Dictyospermum album, and 
Seaforthia elegans, the last species being particularly richly supplied. 
Bundles of fibres of the Raphia-type are generally provided externally with the so- 
called stegmata, under which name Mettenius (17) described certain small cells of the 
. nature of * covering-plates” occuring in Trichomanes. Rosanoff (18) showed that these 
occur commonly in Monocotyledons also. De Bary (6) says * they always appear on the 
outer surface of sclerenchymatous or sclerotie bands of fibres (either such as pursue a 
separate course or accompanying vascular bundles) and are applied to these in longi- 
tudinal rows. The single elements are small and have the form of flat or (in Mono- 
cotyledons) plano-convex, usually rectangular plates with the flat side contiguous 
with the fibrous band. As regards their structure, they are characterized by unequal 
thickening on different sides, usually also by partial silieification of their walls. . . d 
The fibrous bands in the stems, leaves, and roots of . . . . Palms (Chamerops, Pheni«, 
Caryota, &c.) . - . . have interrupted longitudinal rows of plano-convex stegmata ca 
their surface. The convex outer wall of these is thin, the inner thickened to a half- 
SECOND SERIES.—BOTANY, VOL. VI. SR 
