COLOUR AND DEHISCENCE OF THE ANTHER. 251 
they have a flattened leafy body at their base (fig. 532, a); at 
other times the surface of the anther presents projections in the 
form of pointed bodies (fig. 533, a), as in Vaccinium uliginosum, 
or warts, &c. Such anthers, like those which present appendages 
from the connective, are termed appendiculate. 
Colowr of the Anther.—The anther when young is of a greenish 
hue, but when fully matured it is generally yellow. There are 
however many exceptions to this : thus itis dark purple or black 
in many Poppies, orange in Hschscholtzia, purple in the Tulip, 
red in the Peach, &c. 
Dehiscence of the Anther.—When the anthers are perfectly ripe 
they open and discharge their contained pollen (figs. 27, a, and 
535); this act is called the dehiscence of the anther. Dehiscence 
commonly takes place in the line of the sutures (jig. 518, b), and 
at the period when the flower is fully expanded, and the pistil 
consequently sufficiently developed to receive the influence of 
the pollen: at other times, however, the anthers burst before 
the flower opens and while the pistil is still in an imperfect state. 
All the anthers may open at the same period, or in succession ; 
and in the latter case the dehiscence may either commence with 
the outer stamens, as is usually the case, or rarely with the 
inner. 
Dehiscence is produced, partly by the development and growth 
of the pollen in the lobes of the anther pressing upon their 
coats and causing an absorption of their tissue ; and partly by the 
special action of the fibrous cells which form the lining of the 
anther (fig. 521, cf); andit takes place commonly at the sutures, 
because at these parts the endothecium is altogether wanting, 
and the exothecium is also usually very thin, so that they are 
the weakest points of the anther-walls. 
The dehiscence of the anther may take place in four different 
ways, which are respectively called: 1. Longitudinal ; 2. Trans- 
verse; 3. Porous ; 4. Valvular. 
1. Longitudinal or Sutwral.—This, the usual mode of dehis- 
cence, consists in the opening of each anther-lobe from the base 
to the apex in a longitudinal direction along the line of suture, 
as in the Vine (jig. 518, b), the Wallflower (jig. 27, a), and Tulip 
(fig. 523). ev 
2. Transverse.—This kind of dehiscence mostly occurs in 
unilocular anthers, as in those of Alchemilla (fig. 516), Lemna, 
and Lavandula. It consists in the splitting open of the anther 
transversely or in a horizontal direction, that is, from the con- 
nective to the side. It sometimes happens that by the enlarge- 
ment of the connective the loculus of a one-celled anther is placed 
horizontally instead of vertically, in which case the dehiscence 
when it takes place in the line of the suture would be apparently 
transverse, although really longitudinal. An example of this 
kind of dehiscence is afforded by the Mallow (fig. 535), and 
other plants belonging to the natural order Malvacee. In 
