THE STUDY OF TYPICAL FRUITS 183 
216. A Legume, the Bean-Pod.1— Lay the pod flat on the table 
and make a sketch of it, about natural size. Label stigma, style, 
ovary, calyx, peduncle. 
Make a longitudinal section of the pod at right angles to the 
plane in which it lay as first sketched, and make a sketch of the 
section, showing the partially developed seeds, the cavities in which 
they lie, and the solid portion of the pod between each bean and the 
next. 
Split another pod so as to leave all the beans lying undisturbed 
on one-half of it, and sketch that half, showing the beans lying in 
their natural position and the funiculus or stalk by which each is 
attached to the placenta; compare Fig. 146. 
Make a cross-section of another pod through one of the beans, 
sketch the section, and label the placenta (formed by the united 
edges of the pistil leaf) and the midrib of the pistil leaf. 
Break off sections of the pod and determine, by observing where 
the most stringy portions are found, where the fibro-vascular bundles 
are most numerous. 
Examine some ripe pods of the preceding year,? and notice evhere 
the dehiscence, or splitting open of the pods, occurs, whether down 
the placental edge, ventral suture, the other edge, dorsal suture, or 
both. 
217. An Akene, the Fruit of Dock.— Hold in the forceps a ripe 
fruit of any of the common kinds of dock,? and examine with the 
magnifying glass. Note the three dry, veiny, membranaceous sepals 
by which the fruit is enclosed. On the outside of one or more of 
the sepals is found a tubercle or thickened appendage which looks 
like a little seed or grain. Cut off the tubercles from several of the 
fruits, put these, with some uninjured ones, to float in a pan of 
water, and watch their behavior for several hours. What is appar- 
ently the use of the tubercle? 
1 Any species of bean (Phaseolus) will answer for this study. Specimens 
in the condition known at the markets as ‘‘shell-beans’’ would be best, but 
these may not be obtainable in spring. Ordinary “ string-beans’’ will do. 
2 Which may be passed round for that purpose. They should have been 
saved and dried the preceding autumn. 
3 Rumex crispus, R. obtusifolius, or R. verticillatus. This should have 
been gathered and dried the preceding summer. 
