THE FLOWER 37 
Lastly, the anther may be attached by the top to the filament 
and then hang down ; in this case it is pendulous. 
If an anther is cut across and examined with a hand lens, — 
it is seen to consist of two parts, exactly similar to each other, 
and connected together by a continuation of the filament (the 
connective). (See Figs. 35 and 65, ¢.) Hach half-anther 
contains two bags, or sporangia, in which pollen grains, or 
small spores called microspores (Gk. micros, little) are developed. 
When ripe, the anthers open or dehisce to let out the pollen, 
either by a longitudinal slit, or by pores at their apex (as in 
many heaths), or by valves. Occasionally they dehisce trans- 
versely. When the dehiscence takes place towards the inside 
of the flower, it is described as introrse (Lat. introrsus, turned 
in); when on the outer side of the anther, as eztrorse (ex, out). 
Pollen has very much the appearance of fine yellow dust, and 
is usually taken by the wind or insects from one flower to 
another. (See Chapter IX.) 
The carpels are floral leaves which bear the ovules generally 
on their edges. The ovules are sporangia, each ovule con- 
taining oné large spore, the macrospore (Gk. macros, large). In- 
the pea, the gynzcium consists of but one carpel, the two 
edges of which unite to each other to form the chamber 
occupied by the ovules, and therefore called the ovary. In © 
order to-understand the formation of the ovary from a single 
carpel, the two edges of a foliage leaf may be sewn or pinned 
together ; a chamber is then formed. Bearing in mind that 
a carpel is a leaf, and remembering that a foliage leaf has a 
midrib running down the middlo, it will be clear that when a 
—carpel has joined by its edges, the midrib of the carpel will be 
opposite the side where the margins have united. This is 
clearly seen in the pod (Plate IV., Fig. 71). 
The flower of a buttercup consists of many carpels, about 
thirty. The margins of each carpellary leaf unite to form an 
ovary, as in the sweet pea, so that in the buttercup the carpels 
are free, not united to each other, and there are as many 
ovarics as there are carpels. (See Fig. 34.) 
In many flowers, however, the margins of the carpels are 
