ANATOMY OF THE ROOTS OF PALMS. 485 
(59) Cocos RowANzOorrrANA, Cham. 
Essentially similar to C. plumosa, Hook. 
(60) Cocos FLEXvosA, Mart. 
The small roots are essentially similar to those of C. plumosa, Hook., and C. 
Romanzoffiana,Cham. In larger roots the cylinder is incomplete on one side, the free edges 
being incurved, and at this point there is no protoxylem, a single vessel representing the 
xylem-group. Into the medullary tissue opposite toa gap a fibrous mass, containing one 
large vessel and several phloem-groups, is sunk. 
In the centre of the pith are several fibrous strands, each with one, two, or three large 
vessels. The fibrous zone is here much less regular than usual, consisting of partially 
separated wedges, united internally with other fibrous groups containing several vessels, 
but without protoxylem. (Text-fig. 22.) These enclose among themselves little groups 
of parenchyma, shut off from the pith by the growth of fibrous tissue. Many of the 
larger vessels contain thyloses consisting of pitted parenchymatous cells. Similar to 
these are large cells, staining yellow with aniline chloride, occupying irregular spaces 
in the pith. They are almost certainly formed in the same manner as the *thyloses " 
described in the cortical air-spaces of Areca concinna, Thw. 
(61) Cocos BorRYoPHORA, Mart. 
- The outer part of the parenchymatous cortex is comparatively broad and is without 
air-spaces. Through the inner part run irregular small air-spaces. Scattered through- 
out the cortex are isolated, somewhat elongated and lignified parenchymatous elements, 
with square or rounded ends. Just external to the endodermis is a specially well- 
developed layer of these, some few of which are thinner-walled and isodiametrie. The 
endodermis is lignified and followed by a two-layered pericycle, which becomes one- 
layered opposite to the protoxylem. ya i Séi 
te fibrous zone consists of a series of wedges, continuous with one another at the 
i i í tly developed. 
eriphery, but free internally. Xylem V's are frequen ; » 
e “aed internal fibrous groups connected with the inner extremities of the fibrous 
dees occur, each containing a single large vessel. 
vam free medullary fibrous groups of the same nature also occur in the well-developed ` 
pith. dag 
