PHANEROGAMS. 
the result of the lateral coalescence of two stamens. In this case the filaments 
become combined into a central column, on which (as is shown in Fig. 368, ///) the 
pollen-sacs grow more rapidly in length than the filaments, forming vermiform coils. 
The relationships are much more complicated and more difficult to understand 
when cohesion and branching of the stamens occur simultaneously, as in Mal- 
vaceae. In AlthoBa rosea, for instance, the filaments form a membranous closed 
tube which completely envelopes the gynaeceum; springing from this tube are five 
vertical and parallel double rows of long filaments, each of which (Fig. 369, E) 
again splits into two arms (/), and each of these arms bears a single anther-lobe. 
The history of development and a comparison with allied forms shows that the tube 
is formed by the lateral coalescence of five stamens ; but the coherent margins produce 
double rows of lateral ramifications, in other words, of filaments, which then again 
split into two arms. A horizontal section of the young staminal tube (Fig. 369, A) 
shows plainly these double rows of split filaments ; the part (z;) which lies between 
two of these must be considered as the substance of a stamen, the margins of which 
Fig. jßg.—Althaa rosea ; A horizontal section through the young andrcecium ; D a piece of the tube of a mature 
androecium with several stamens; h cavity of the tube, v substance of the tube, a anthers, t the spot where the 
filament divides, ythe spot where two filaments spring from the tube (A much more strongly magnified than />'). 
each bear right and left a simple row of filaments as laciniae or branches^. In 
the Lime, where the five primordial stamens also branch at the margins, and form 
anthers on their branches, the stamens remain free, but in other respects the 
phenomena are altogether similar {cf. Payer, /. <:.) 
The stamens not unfrequently suffer conspicuous displacements by the inter- 
calary growth of the tissue of the receptacle in the region of their insertion ; and 
such displacements are also ordinarily included under the term cohesion (or adhe- 
sion)^. Thus the stamens often adhere to the calyx or corolla; and then, when 
' The strangeness of this conception will disappear if the structure is recalled of a unilocular 
ovary with numerous carpels coherent at the margins, e. g. Viola, where the ovules arise in double 
rows on the lines of junction (the placentae). What takes place in one case in the inside in reference 
to the ovules takes place in the other case on the outside in the formation of the filaments. 
^ [It has come to be the usage in English works on descriptive botany to apply the term 
' cohesion ' to the apparent union of organs of the same kind, ' adhesion ' to the apparent union of 
organs of a different kind.] 
