50 
SEED DISPERSAL. 
30. Shot off by wind or animal. — The calyx of sage, 
bergamot, and most other mints, remains dry and stiff, as 
a cup to hold one to four little round nutlets as they 
ripen. The figure shows two of these in section, as they 
are attached to the main stem of the plant, or one of its 
branches. Observe the di- 
rection taken by the upper 
and by the lower points of 
the calyx. When dry, the 
plant behaves somewhat as 
follows: when the wind 
jostles the branches against 
each other, or when an ani- 
mal of some kind hits the 
plant, this movement causes 
many of these cups to get 
caught ; but the elastic stem 
comes suddenly back to its 
place, and in so doing flips a nutlet or more from its 
mouth one to six feet, somewhat as a boy would flip a 
pea with a pea-shooter. In our garden, July 2, when 
plants of sage, Salvia interrupta, were ripening their 
fruit, we found it difficult to collect any seeds, but 
seedlings were observed in abundance on every side of 
the plant, some to the distance of six feet. Plants dis- 
persing seeds in this manner have been called catapult 
fruits. Examine ripening fruits of blue curls, pennyroyal, 
germander, balm, horehound, dittany, hyssop, basil, mar- 
Fig. 39. — Ripe calyx of sage, first as pushed 
down ; second as let loose throwing nutlets. 
