The Bractless Inflorescence of the Cruciferce 153 
formed beneath some of the lower flowers at varying levels from the 
base of the pedicel upwards (Figs. 3-4), a faint decurrent outline 
indicating the delimitation of the downward extension below the 
exsertion point (Fig. 4). The indeterminate position is due to a pro¬ 
longed fusion of the bract process with the pedicel which it subtends, 
and the consequent carrying up of the exsertion point. [It may be 
noted in passing that some amount of fusion of the lowermost pedicels 
with the main axis is also of common occurrence, and was evidently 
present in the specimen of the Stock used for the illustration in 
Bessler’s Hortus Eystettensis 1 .] In the hoary type these processes are 
easily overlooked owing to their being partly imbedded in the felt- 
work of hairs (Figs. 10-11), but in glabrous individuals they stand 
out conspicuously (Figs. 12-13). In a glabrous plant which has the 
constitution CRH the otherwise hairless process may bear at its apex 
one characteristically branched hair like the ordinary foliage leaves 
in this strain 2 (Fig. 13). The process is clearly the very much re¬ 
duced free region of a subtending leaf (bract). It contains no vascular 
tissue and but little chlorophyll, and constitutes merely a very simple 
hydathode, for two or three water pores are generally present. Except 
for this latter feature, it is remarkably like the rudimentary leaf 
structures in Psilotum triquetrum. Immediately below the exsertion 
level the undisturbed vascular ring of the stem lies slightly further 
from the surface than at other points of the circumference, owing 
to the slight increase in bulk of cortical tissue forming the downward 
continuation of the process. Such bract-processes are not restricted 
1 Classis aestivalis, fol. 33, 2, 1640. 
2 See J. of Genetics, 10, p. 159, text-figure 1, also PI. VIII, Figs. 7 and 8. 
C and R denote the two factors required to produce coloured sap. H =one of 
the factors for hoariness. 
Description of Text-figures on p. 152. 
Figs. 1-2, Cheivanthus Cheivi. Fig. i, a flowering shoot with a bract-process 
accompanying the lowest flower; the downward extension of the process 
can be traced to the mid-axil of the fifth leaf below as usual in a f arrange¬ 
ment. [The similar demarcation lines from the foliage leaf insertions are 
not shown in the drawing.] Fig. 2, portion of the same showing the bract- 
process more highly magnified. N.B. Figs. 3-9, Matthiola incana. Figs. 3-4 
show a bract-process accompanying the flower and fused for some distance 
with the pedicel. Fig. 5, the lowest flower in the raceme subtended by a 
foliage leaf. Fig. 6, young inflorescence accompanied by a sickle-shaped 
leaf which is half foliage leaf, half sepal in form. Fig. 7, a sickle-shaped leaf 
• more highly magnified showing the crinkled membranous border charac¬ 
teristic of a sepal along the concave edge. Fig. 8, a shoot bearing a flower 
accompanied by a “sepal-bract.” Fig. 9, a “sepal-bract” overarching a 
young inflorescence and thus causing the axis to become curved. 
