ON THE ANATOMY OF CHENOPODIUM ALBUM L. 
Ernst If. Artschwager 
Introduction 
The Chenopodiaceae and related families exhibit a most striking anom- 
alous structure of the stem in that the annual secondary thickenings 
contain several circles of collateral vascular bundles of limited develop- 
ment which are embedded in lignified so-called "conjunctive tissue." 
Gheorghieff (i) in a series of publications gives a detailed review of 
the early literature on this subject. His own contributions, furthermore, 
comprise the most comprehensive study of the anatomy of the Chenopodi- 
aceae. He finds that the plants which he examined show greatly varied 
forms, transitional in structure to many of the Centrospermae. 
Sanio (2) in 1863 gives the most complete ontogenetic study of members 
of the Chenopodiaceae. He attributes the anomalous structure of the 
stem to the activity of a periodically acting cambium which produces 
collateral vascular bundles and "conjunctive tissue." At the conclusion 
of his work Sanio draws a comparison between the anomalous stem structure 
of the Chenopodiaceae and the stem structure of these monocotyledons 
which are characterized by growth in thickness. 
In his "Comparative Anatomy of the Phanerogams and Ferns," De 
Bary (3) develops a theory to account for the diverse forms of anomalous 
growth of the vascular tissue of Chenopodiaceae and related' families. He 
makes four general classes. In the plants of the first grcup, an extrafascic- 
ular cambium appears around the primary ring of leaf-trace bundles. 
This cambium remains permanently active and forms alternately on its 
inner side collateral vascular bundles and conjunctive tissue; on its outer 
face it forms a thin layer of phloem or none at all. The plants of the second 
type develop a ring of primary vascular bundles with normal cambium. 
The activity of the latter soon ceases, and on the outer face of the primary 
ring appear in centrifugal order a succession of cambia each of which forms 
a distinct ring of vascular bundles and intermediary tissue. Classes three 
and four are types intermediate between the first two. 
Morot (4) points out that the two modes of growth described by De 
Bary may be reduced to one type. The cambium in each case retains its 
bipolarity, giving rise to xylem on the inside and phloem on the outside. 
Fron (5) subsequently states that the stem of Chenopodium album in- 
creases in diameter by the activity of a normal and pericyclic cambium, 
and that this cambium produces to the inside xylem and parenchyma and 
to the outside phloem tissue. 
