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“62 | ELEMENTARY BOTANY 
a dry, dehiscent fruit, formed of one carpel, and dehiscing 
along both the midrib and the margin (Plate IV., 
Wee Ps. | | 
2. A follicle is similar to a pod, except that it dehisces 
along the margin alone and not along the midrib. Follicles 
usually occur in compound fruits, as Christmas rose, Peony, 
~ Marsh Marigold, Columbine (Plate IV., Fig. 76). 
3. The siliqua, characteristic of the order Crucifere. This 
may be examined in the Wallflower, or pod of almost any 
Crucifer, such as Mustard, Jack by-the-hedge. At the bottom 
of the fruit is a ridge, where the sepals, petals, and stamens 
of the flower were attached; the fruit is therefore superior. 
It dehisces from the base upwards, along the edges of the two 
carpels into two valves, each having its own midrib. The 
seeds are attached to a thin membrane, called the replum, 
which lies parallel to the valves, and remains after they have 
fallen off. The replum must not be confused with the 
partition which is often seen between the valves of a fruit, 
and which is formed from the turning in of the carpellary leaf, 
as already described in the ovary of the Tulip (p. 38). The 
replum is an outgrowth from the edge of the carpel, but it is 
not part of the carpel itself; it is found in the majority of the 
Crucifere (Plate IV., Fig. 72). When a fruit of this kind 
is nearly as broad as it is long, then it is called a silicula, 
which is similar in all essential respects to the siliqua. The 
fruit of the Pennycress, Honesty, Shepherd’s-purse is a silicula 
(Plate TV; Vies. (3-74: 
4. The term capsule is applied to those dry, dehiscent fruits 
which consist of two or more carpels, ¢.g., Figwort, Violet. 
Capsules proper are usually classified according to their 
~ mode of dehiscence : 
I, They may dehisce lengthways along the margin, @9., 
Figwort (Plate IV., Fig. 75). 
2. They may dehisce lengthways along the midrib, e.9, 
Iris (Fig. 81), Lily, Pansy (Fig. 78). 
3 They may dehisce by teeth, ¢.g., Chickweeds and many 
other Caryophyllacez (Plate IV., Fig. 80). 
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