[ 150 ] 
THE BRACTLESS INFLORESCENCE OF THE 
CRUCIFERS 
By EDITH R. SAUNDERS 
Fellow of Newnham College, Cambridge 
(With Plate III and 9 figures in the text) 
I N a recent communication 1 dealing with the significance of certain 
superficial features exhibited in the stems of a large number of 
the higher plants and occasionally also in the hypocotyl, it was 
shown that in anatomical evidence of the kind indicated we have 
clear proof that the entire surface of the shoot axis is composed of 
the extensions of the leaf areas below the point of exsertion—to use 
the very appropriate term recently employed by other writers. For 
in some species these downward extensions, which are fused internally 
with the axis tissue proper and laterally with each other, have their 
potential edges demarcated by visible anatomical indicators such as 
hair, ridge and colour lines. At the same time it was realised that 
certain well known exceptional constructions might appear not to 
be covered by the above generalisation, and to need further investi¬ 
gation. One such case would seem to be furnished by the so-called 
bractless raceme of the Cruciferse, of which we have a typical example 
in the Stock (Matthiola incana). But though the (apparently) bract¬ 
less condition is a very general feature in Cruciferous inflorescences, 
it is to be noted that this apparent total suppression of all bracts is 
by no means universal in this family. Many cases are enumerated by 
Godron 2 where larger or smaller bract structures have been observed, 
and according to this author a bract, generally rudimentary but 
sometimes more or less well developed, is quite frequently present. 
He further notes the not infrequent occurrence in the inflorescence 
of decurrent ridge lines from the bract margins and midribs similar 
to those starting from the leaf insertions, and comments upon the 
fact that these features are sometimes observable even when the bract 
is undeveloped 3 . (Viewed from the standpoint of the “Leaf-skin” 
theory, these contour lines no longer present a difficulty, see foot- 
1 The Leaf-skin Theory of the Stem, Annals of Botany, 36 , p. 135, 1922. 
2 Ann. Sci. Nat. 2, p. 281, 1864. 
3 See also Norman, Ann. Sci. Nat. 9 , p. 124, 1858. 
