562 PHANEROGAMS. 



Stem, especially when kept moist and dark, enables them to be reproduced to almost 

 any extent from branches and portions of branches. Some species climb, like the 

 ivy, by roots put out regularly from the weak stem which requires a support ; others 

 send out runners to a distance, on which the bud forms a new plant, as in the straw- 

 berry, the stem which is thus formed putting out roots. The order of succession of 

 new roots from the stem is in general acropetal^ but they do not usually make their 

 appearance except at a considerable distance behind the growing bud ; many Cac- 

 taceae however not un frequently produce them close below it. 



The norm^al Mode 0/ Branchmg at the end of growing shoots is monopodial ; 

 the branches are produced laterally beneath the apex of the punciiim vegetatiojiis. 

 Up to the present time only one instance is known of dichotomous branching, and 

 in that the bifurcations are developed sympodially ; according to Kaufmann, the 

 formation of the circinate inflorescence of Borragineae depends, as has already been 

 mentioned, on this mode of development. The normal monopodial branching is 

 axillary; the lateral shoots are produced in the angle which the median line of 

 the leaf forms with the internode. On a vegetative shoot at least one lateral 

 shoot is produced in the axil of each leaf, although only a few of the axillary buds 

 unfold. Sometimes other axillary buds are produced in rows above the original 

 one; as, for instance, above the axils of the foliage-leaves in Aristolochia Sipho, 

 Gleditschia, Lonicera, &c.\ above the axils of the cotyledons in Juglans regia, 

 and that of the larger cotyledon in Trapa. In woody plants the axillary buds 

 destined to live through the winter are not unfrequenlly so completely surrounded 

 by the base of the leaf-stalk that they are not visible until the leaf has fallen off, 

 as in Rhus iyphinum, Virgilia lu/ca, Platanus, &c., and are then called Intrapetiolar 

 Buds. Besides the ordinary axillary branching, some cases are known among 

 Dicotyledons of lateral and monopodial but extra-axillary branching. To this 

 description belong the tendrils of Vitis and Ampelopsis which are produced (accord- 

 ing to Niigeli and Schwendener) beneath the punctum vegetatmiis of the mother- 

 shoot, opposite to the youngest leaf and somewhat Inter than it. In Asclepias 

 syriaca and some other plants a lateral vegetative branch stands beneath the 

 terminal inflorescence between the insertions of the foliage-leaves, which themselves 

 also produce shoots in their axils. According to Pringsheim^ lateral shoots arise 

 on the concave side of the long spirally-curved vegetative cone of Utricularia 

 vulgaris which he considers to be extra-axillary branches, while 'normal' shoots 

 are formed in the axils of the leaves which stand in two rows on the convex side 

 of the shoot or by their side. It appears to me however certain that these extra- 

 axillary structures on the concave side of the mother- shoot are leaves of peculiar 

 form^, since inflorescences are produced in their axils. 



The suppression of the bracts of the inflorescence, which is not uncommon, 



» See Guillard, Cull. Soc. Cot. de Frar.ce, vol. IV, 1857, p. 239 (quoted Ly Duchartre, Elements 

 do Cotanique, p. 408). 



2 Zur Morphologie der Utriculai ien, Monalsber. der kr-nigl. Akad. der Wissensch. Feb. 1 869. 



^ This of course depends on what is considered leaf and what shoot; this is not however a 

 matter of simple observation, but rather of conventional conceptions convenient for a special 

 purpose. 



