DEVELOPMENT OF THE MEMBERS OF A BRANCH-SYSTEM. 1 85 
recognised only on the youngest branches, since the bifurcations are developed sym- 
podially, and in fact as scorpioid cymes. This often happens (as in Selaginella 
flabellata) in such a manner that the entire outline of a branch consisting of nume- 
rous bifurcations assumes a form similar to that of a multipinnate Fern-leaf. The 
student who desires to obtain a clear idea of the different modes of development of 
a system produced from a dichotomous origin, and especially of the formation of 
sympodial forms out of dichotomies, could find no better object of study than the 
Selaginellese which are cultivated in all hot-houses. On the branching of the stem of 
Ferns and Rhizocarps, reference should be made to the description of the respective 
classes in Book II. 
The branching always originates monopodially in the stems of Characea^, Equiseta- 
cese, and Coniferse, and here also its future development is always racemose. The 
branch-systems of Mosses also always originate monopodially, but are sometime developed 
sympodially (as the ' innovations' of Acrocarpous Mosses beneath the sexual organs). It 
is often very irregular, but is sometimes of such a nature that much-branched systems 
of shoots develope racemosely and assume defined outlines, like those of multipinnate 
leaves, as in Hylocomium, Thuidium, &c. 
The branching of Monocotyledons and Dicotyledons is always originally monopodia!, 
but the mode of development of the system is extraordinarily variable ; on the same plant, 
and even on the same branch-system, different forms, both racemose and cymose, may 
arise. The peculiarities of the different forms of development are usually very con- 
spicuous in inflorescences, and are of many different kinds ; and since the attention of 
botanists has been turned for a long time in this direction, they are not only copiously 
employed in the description of plants, but also furnished with names, which are here 
used in a more general sense. A more special description of those branch-systems 
which, in the case of Flowering Plants, are called Inflorescences, will ioWow in the general 
consideration of Angiosperms in Book II ; here it is only necessary to mention that the 
forms distinguished as spikes, racemes, and panicles are examples of the racemose 
development, while those termed dichasia, cymose umbels (in Euphorbia), and 
scorpioid and helicoid cymes, are examples of the cymose development of branch- 
systems which are at first monopodia!. 
Every other form of vegetative branching of Flowering Plants may be regarded from 
the same point of view. The formation of sympodia is not unfrequently brought 
about by arrest of the growth of the terminal portion or bud of the shoot, while the 
nearest lateral bud developes more vigorously, and appears like a continuation of the 
mother-shoot, as in Robinia, Corylus, Cercis, and many other plants ; in the lime the 
primary stem itself is a sympodium formed in this manner. If the flower-bearing shoots 
above ground die annually, while the underground portions remain in a living condition, 
underground sympodia sometimes arise composed of the comparatively short but thick 
basal portions of numerous larger shoots which have long since died off. This is the case, 
for instance, in Polygonatum multiflorum, the underground stem of which is known under 
the name of Solomon's Seal. In Fig. 143 is represented the anterior portion of one of 
these underground stems, those produced during eight previous years having been re- 
moved. The stem denoted by b 1866 is the lower portion of the upright aerial shoot 
bearing leaves and lateral flowers, which was in existence in that year ; but this shoot is 
itself only the terminal part, its much thicker basal portion is denoted in the diagram JS 
(as seen from above) by « + 2 ; the slenderer terminal part dies off in the autumn, and at 
h, b, beneath the numbers 1864 and 1865, are shown the scars which remain behind 
after the death of the similar earlier terminal parts. The portion of the sympodium 
here represented thus consists of the three basal portions «, « + i, « + 2, of three shoots, 
each of which unfolded its aerial portion bearing leaves and flowers in the year indicated. 
In the same manner the bud « + 3 will now develope further ; it springs from the axil 
of the leaf, the scar or insertion of which is denoted by 9". The basal portion of the 
shoot which proceeds from it will add a new piece to the sympodium, its terminal part 
