23 



where on the young frond. Their color is brown-red in the cen- 

 tral part of the nectarial surface, developing into red on the edges. 

 Later the red color is lost, and the organs are then deep green. 

 The secretion of nectar is very abundant during the unfolding of 

 the frond. So abundant is it in fact, that large beads of the limpid 

 fluid may be seen from a distance, resting on the nectaries or run- 

 ning down the petiole. With a hand lens, one may easily note 

 the accumulation of nectar after the surface has been wiped off. 

 Darwin found that a drop of the liquid was formed in six minutes. 

 Handling and tasting the secretion shows it to be sirupy and very 

 sweet. According to Bonnier the sugars saccharose and glucose 

 are present. Here, as in analogous organs in other plants, the ex- 

 udation is quite independent of bleeding pressure. Leaves which 

 have been broken off continue to produce nectar for some days, 

 provided, of course, that they be kept in fair condition. As the 

 frond ages, the activity of the glands is lowered, until they 

 finally cease to secrete and become functionless as nectaries." 



Prof. Lloyd finds the surface of the glands to have a dozen or 

 more pores scattered over them from which the sugary solutions 

 ooze, and believes the pores to be similar to the ordinary "breath- 

 ing pores" (stomata) of the leaf. In the bracken the stomata 

 are absent from the stems except for two bands of stomata, one 

 on either side of the flattened upper side of the stems, and the 

 glands arise at points along these bands. In offering an explana- 

 tion for the presence of the nectaries the author says : "F. Muller 

 pointed out that in Brazil the fern is visited by an ant of which 

 a leaf-cutting species stands in dread. To this Francis Darwin 

 answers that the plant has few natural enemies — meaning, pre- 

 sumably, in England, though this is equally true, so far as ob- 

 servation goes, in North America. Francis Darwin further sug- 

 gests, in view of the possible weakness of the above explanation, 

 that the gland is either an organ which was formerly of use and 

 is now passing away, or that it is connected 'with some un- 

 known process of nutrition. That its activity 'is decidedly con- 



