80 FRUITS 



the number of carpels can generally be determined by 

 the number of sutures or of placentas. The placenta 

 is not always formed by the margins of the carpels, how- 

 ever, but sometimes the seeds are borne upon a prolonga- 

 tion of the receptacle, as in the pink and the corn cockle 

 (Fig. 178), forming ^ free central placenta. A free central 

 placenta may also be formed when the carpels of a pod 

 break away from the seed-bearing surface, as in Figures 

 169 and 170. 



PRACTICAL QUESTIONS 



1. Can you name any syncarpous, or compound capsule that is single- 

 seeded ? 



2. Can you name any indehiscent fruit that has more than one 

 seed? 



3. Name the weeds of your neighborhood that are most troublesome 

 on account of their adhesive fruits. 



4. Do they belong, as a general thing, to the dehiscent or the inde- 

 hiscent class? 



5. Give a reason for these facts. 



ACCESSORY, AGGREGATE, AND COLLECTIVE FRUITS 



Material. — If snake strawberries {Fragaria indicd), Osage orange, 

 and other late fruits of the kind cannot be obtained, a pineapple may 

 be used for the whole class. Fresh figs, if they can be obtained, make 

 good objects for study, but dried ones may be used. Hips, haws, 

 etc., are always plentiful at this season. As many of the fruits men- 

 tioned in the Practical Questions as can be obtained should be studied 

 either in or out of class. 



110. Besides the varieties already named, all fruits, 

 whether fleshy or dry, may be either simple, accessory, 

 aggregate, or collective. The first kind need no explana- 

 tion ; they consist merely of a single ripened ovary, 

 whether of one or more carpels, as the peach, cherry, 

 bean, lemon, etc. 



111. Accessory Fruits are so called because some other 

 part than the seed vessel, or ovary proper, is coherent 

 with or accessory to it in forming the fruit, as we saw in 



