598 
PHANEROGAMS. 
dichotomy of the apex of an axillary bud ; and Kraus has also shown that the leafless 
inflorescence of Heliotropium and Myosot'is is a monopodium, at all events when luxu- 
riant. A thick and flattened vegetative cone developes two alternate rows of flowers 
on its upper side ; on this side the longitudinal growth of the primary axis is at first 
stronger; and the younger part of the inflorescence is consequently rolled with its apex 
downwards in a circinate manner. An inflorescence which is formed in this manner, 
as will be seen from what has already been said, cannot properly be described as a 
scorpioid cyme, but corresponds rather to a raceme or spike which bears flowers only 
on one side of its rachis. The leafy scorpioid cymes of Anchusa, Cerintke, Borago, 
and Hyoscyamus are, on the contrary, the result of dichotomous branching; a leaf 
which stands on the primary axis ending in a flower bears in its axil a vegetative cone 
which is at first hemispherical ; this becomes broader and dichotomises in a direction 
parallel to the surface of the leaf; one of the bifurcations becomes a flower, the other 
bears a new leaf at right angles to the last, and forms a dichotomy above it as before. 
The planes of dichotomy therefore cross one another at right angles ; and this is the 
reason why the leaves always stand between the sympodial axis and the flower. Lateral 
displacements of the leaves begin at the second division and continue afterwards. 
According to Kraus it is doubtful whether the sympodial inflorescences of Ompba- 
lodes and Solanum nigrum are the result of dichotomous or of lateral branching. On 
the side of the primary axis which becomes a flower a leafless lateral axis arises which 
continues to branch, and the right and left lateral axes of which are alternately trans- 
formed into flowers. Kraus entertains a similar doubt respecting weak inflorescences 
oi My OS Otis and Heliotropium {"vide supra). 
It will be seen from what has now been said, that within an inflorescence which 
consists of several orders of axes there may be produced not only diff'erent forms 
of one section, but forms belonging to both sections {A and B), mixed inflorescences 
being thus formed. Thus, for example, a panicle may form dichasia in its last ramifi- 
cations (as in some species of Silene) \ a dichasium may bear capitula {e.g. Silphium), 
or even in its first branches or in those of a higher order may pass into a helicoid 
or scorpioid cyme (as in Caryophyllese, Malvacese, Solanaceae, Linaceae, Cynanchum^ 
Gagea, Hemerncallis, &c.). The mode of branching of the inflorescence is in most 
cases different from that of the vegetative stem. Not unfrequently it passes abruptly 
from one to the other, but often through intermediate modes of branching. 
In the older systems of nomenclature a number of other terms are given to various 
forms of inflorescence, such as glomerulus, corymb, &c. ; but they all designate merely 
the habit or external form of the system, and must be referred, in a scientific description, 
to one or other of the above forms or to combinations of them. 
2. With regard to the Change in the Mode of Branching accompanying the transition 
from the vegetative to the floral region of a shoot. Warming gives some very valuable 
information in his Recherches sur la ramification des Phanerogames (Kopenhagen 1872), 
from which it appears that the numerous cases of extra-axillary branching in in- 
florescences can be referred to axillary branching as the typical mode. He lays it down 
that the axillary branch with the corresponding leaf are to be regarded as a whole, one 
branching usually takes place in weak inflorescences. Goebel (Arb. d. Bot. Inst, in Würzburg, II, 
1880) finds not only that Kraus' account of the development ot the inflorescence of Myoso/Zs and of 
Heliotropium is accurate, but that it applies also to that of Syinphytum officinale, Arichusa, Cerintke, Borago, 
Cynogloss7an, Echium vidgare, Lithosperrmcm arvense, and Caryolopha sempervirens ; the development of 
the flowers is lateral also in Hyoscyamus niger, Klugia Notoniana, and in Heliatithemum. Goebel's con- 
clusions have been combated by Celakovsky (Flora, 1880). It must be borne in mind that dichotomous 
and lateral branching are not absolutely distinct forms, but that they are connected by intermediate 
conditions, so that they gradually merge one into the other. (See also Henslow, On the Origin of 
the so-called Scorpioid Cyme, Trans. Linn. Soc, 1880; and the History of the Scorpioid Cyme, 
Journ. of Botany, 1881.)] 
