BRACTS AND FLORAL LEAVES. 85 
upon simply as the free lobes of the calyx. In a perigynous 
flower, therefore, the petals and stamens were regarded as 
adherent to the calyx. The union between the hollow receptacle 
and the gynecium (p. 81) in an epigynous flower was similarly 
taken to be an adhesion between “calyx tube” and gynecium. 
In this case the calyx was termed “superior,” because its 
“lobes” had a position obviously above the adhering part of 
the gynecium. In other cases it was called “inferior.” 
External Characters.—The calyx may be radially or bilaterally 
symmetrical. When polysepalous, the individual sepals can be 
described in the terms used for foliage leaves. They are never 
stalked, but may possess stipules at their points of attachment. - 
These, if large, look like an outer whorl of sepals, which receives 
the name epicalyx, as in strawberry and marsh-mallow. An epi- 
calyx may also be formed by bracteoles. The sepals are some- 
times divergent or spreading, as in the tallest form of buttercup 
(Ranunculus acris), or again they may be reflexed, t.e., bent back, 
of which another common kind of buttercup (Ranunculus bulbosus) 
is an example. Sepals are frequently more or less swollen or 
saccate at their base. This is the case with the two lateral sepals 
of wallflower and shepherd’s purse. Such a swelling may be 
exaggerated into a tubular structure termed a spur, which is then 
usually a nectary, secreting honey on its inner surface. In the 
buttercup, as we have seen (p. 74), the nectaries form part of the 
petal, and indeed these organs vary very much in position accord- 
ing to the kind of plant examined. In some cases they are found 
away from the flower altogether. Examine the bilaterally sym- 
metrical calyx of a pelargonium, first removing the petals. Five 
sepals will be seen, a large pair on the anterior side, then a 
smaller pair, and lastly, a much larger unpaired posterior one. 
By looking down upon the calyx a small hole will be seen be- 
tween the odd sepal and the pink structures in the centre of the 
flower. A needle pushed into this will enter a short tube which 
can be seen as a ridge on the outside of the flower-stalk. A 
transverse section at this point will show both tube and stalk. 
We have here a spuz’, belonging to the posterior sepal, and firmly 
adherent to the flower-stalk. A spur, however, is not always a 
nectary. In the larkspur there are five large blue sepals, the 
posterior one of which is produced into a large spur. This 
simply serves as a cover to two small spurred petals, parts of 
which, together with two small unspurred petals, are seen in the 
centre of the flower. Monkshood is somewhat similar. The 
“hood” formed by the posterior sepal encloses two small petals 
(here the only ones), which are entirely changed into nectaries. 
When the calyx is gumosepalous the united part forms a tule 
