128 DROSERA ROTUNDIFOLIA. CHAP. VI. 



much inflection ; on the contrary, this served to a certain extent 

 as a protection to the seeds. Two of the six seeds germinated 

 whilst still lying on the leaves, but the seedlings, when trans- 

 ferred to damp sand, soon died ; of the other four seeds, only one 

 germinated. 



Two seeds of mustard (Sinapis nigra), two of celery (Apium 

 graveolens) both of the previous year, two seeds well soaked of 

 caraway (Caram carui), and two of wheat, did not excite the 

 leaves more than inorganic objects often do. Five seeds, hardly 

 ripe, of a buttercup (Eanuncuhis), and two fresh seeds of Ane- 

 mone nemoros't, induced only a little more eifect. On the other 

 hand, four seeds, perhaps not quite ripe, of Carex nyluatica caused 

 the leaves on which they were placed to be very strongly in- 

 flected; and these only began to re-expaud on the third day, 

 one remaining inflected for seven days. 



It follows from these few facts that different kinds of seeds 

 excite the leaves in very different degrees; whether this is 

 solely due to the nature of their coats is not clear. In the case 

 of the cress seeds, the partial removal of the layer of mucus 

 hastened the inflection x>f the tentacles. Whenever the leaves 

 remain inflected during several days over seeds, it is clear that 

 they absorb some matter from them. That the secretion pene- 

 trates their coats is also evident from the large proportion of 

 cabbage, raddish, and cress seeds which were killed, and from 

 several of the seedlings being greatly injured. This injury to 

 the seeds and seedlings may, however, be due solely to the acid 

 of the secretion, and not to any process of digestion ; for Mr. 

 Traherne Moggridge has shown that very weak acids of the 

 acetic series are highly injurious to seeds. It never occurred 

 to me to observe whether seeds are often blown on to tho viscid 

 leaves of plants growing in a state of nature; but this can 

 hardly fail sometimes to occur, as we shall hereafter see in the 

 case of Pinguicula. If so, Drosera will profit to a slight degree 

 by absorbing matter from such seeds. 



Summary and Concluding Remarks on the Digestive 

 Power of Drosera. 



When the glands on the disc are excited either 

 by the absorption of nitrogenous matter or by 

 mechanical irritation, their secretion increases in 

 quantity and becomes acid. They likewise transmit 



