LESSON 30.] 



THE BUTTERCUP. 



183 



Buttercup ; the plan of the veins is just as in Fig. 50, only the leaf 

 is very deeply cut, in most species. The character of the stem is not 

 quite so easy to make out in an herb as it is in a shrub or tree.' In 

 these we see at a glance what an exogenous stem is (424-426) : 

 besides, the stem of the Buttercup is generally hollow, and so the 

 pith is partly broken up. Still, if we make a slice near the base, 

 and view it under a magnifying-glass, we shall find that, although 

 herbaceous, it is formed on the same plan as that of Maple (Fig. 

 353) or any common wood. It is just as in Fig. 352, only there is 

 not so much wood in it ; but what there is evidently forms a ring 

 between a pith in the centre and an outside bark ; so it is exogenous. 

 The embryo, in the seed of 

 the Buttercup, is too minute 

 for the student to find without 

 considerable practice in dis- 

 secting seeds : so that charac- 

 ter must be passed by. But 

 the five leaves of the calyx 

 and the five petals plainly 

 show that the flower is con- 

 structed on the plan of five. All this agrees with Class I. ; so we 

 may be sure our plant belongs to that class. 



529. Under this class are two subclasses. Subclass I. ANGTO- 

 SPERMJE, has regularly closed pistils, the ovary forming a case which 

 includes the ovules or young 

 seeds. To get a good view 

 of the parts, let us with a 

 sharp knife cut a flower di- 

 rectly through the middle from 

 top to bottom ; as in Fig. 358. 

 We see it has a cluster of many pistils, heaped on an oblong recep- 

 tacle : some are left whole ; some are divided. One pistil, with the 

 wall of the ovary cut away on one side, is shown, more magnified, in 

 Fig. 359, bringing to view the single ovule it contains. The other 

 subclass (mentioned on page xxiii) has an open scale for a pistil, 

 bearing naked ovules, such as is shown in Fig. 264 and Fig. 266. 



FIO. 358. A flower of a Buttercup (Ranunculus bulfoosus) cut through from top to bot- 

 tom, rind enlarged. 359. A pistil taken from it, and more magnified ; its ovary cut through 

 lengthwise, showing tho ovule. 3fiO. One of its pistils when ripened into a fruit (achcnium'). 

 361. The same, cut through, to show the seed in it. 



359 



