156 
ORGANOGRAPHY. 
BOOK I. 
This is only known to exist in Araceae and Palms. It is fre- 
quently terminated, as at Jig. 83., by a soft club-shaped mass 
of cellular substance which extends far beyond the flowers, 
and is itself entirely naked ; this is an instance of a grow- 
ing point analogous to what forms the spine of a branch, 
except that it is soft and blunt, instead of being hard and 
sharp-pointed. 
The raceme has been said to differ from the spike only in 
its flowers being pedicellate : to this must be added, that the 
pedicels are all of nearly equal length ; but in many plants, as 
Alyssum saxatile, the lower pedicels are so long that their 
flowers are elevated to the same level as that of the upper- 
most flowers ; a corymb is then formed (Jig. 87.). This term 
is frequently used in an adjective sense, to express a similar 
arrangement of the branches of a plant or of any other kind 
of inflorescence : thus, in'Stevia, the branches are said to be 
corymbose ; in others, the panicle is said to be corymbose ; 
and so on. When corymbose branches are very loose and 
irregular, they have given rise to the term muscarium ; a name 
formerly used by Tournefort, but not now employed. 
If the expansion of an apparent corymb is centrifugal, in- 
stead of centripetal ; that is to say, commences at the centre, 
and not at the circumference, as in Dianthus Carthusianorum, 
we then have fascicle (fig. 84.); a term which may not 
incorrectly be understood as synonymous with compound co^ 
rymb. The modern corymb must not be confounded with that 
of Pliny, which was analogous to our capitulum. 
When the pedicels all proceed from a single point, as in 
Astrantia, and are of equal length, or corymbose, we have 
an umbel (fig. 80.). If each of the pedicels bears a single 
flower, as in Eryngium, the umbel is said to be simple 
(fig. 79. a) ; but if they divide and bear other umbels, as in 
Heracleum, the umbel is called compound ; and then the as- 
semblage of umbels is called the universal umbel, while each 
of the secondary umbels, or the umbellules, is named a par- 
tial umbel. The peduncles which support the partial umbels 
are named radii. Louis Claude Richard confined the word 
umbel lo the compound form, and named the simple umbel 
sertulum ; but this was an unnecessary change. 
