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 Selaglnella 

 Jiabellata) 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 

 Selaginelleae 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 Gharaceae, Equiseta- 

 ceae, 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 monopodial, 

 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 

 lused, in a more general sense. A more special description of those branch-systems 

 which, in the case of Flowering Plants, are called Inflorescences, will follow 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 monopodial. 



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 

 rprimary stem itself is a sympodium formed in this manner. If the flower-bearing shoots 

 1 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 Po/ygonatum mult'iflorum, 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 B 

 (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 n, n+ i, n + 2, oi 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 



