1883.] NATURAL SCIENCES OF PHILADELPHIA. 191 



anywhere about it. This caused a reexamination of the wl\oIe 

 case, when it was noticed that stones under the spruce tree, 

 forming the shore of the river, and many feet outside of the circle 

 formed by the branches of the Pyrus and Alder, were quite black 

 with a gummy coat, which most probably had fallen from the 

 spruce, the branches of which overshadowed the two bushes already 

 named, as well as the stones. The branches of the spruce hanging 

 towards the river were covered with young cones of probably 

 one-half their full size, and the scales were found to be filled with 

 sweet liquid. Taking the cone as it hung on the tree and stripping 

 it down as one would milk a cow, a drop as large as a pea gathered 

 in the hand from a single cone. There could be no doubt but that 

 the viscid covering on the leaves of the two shrubs below, as well 

 as on the unprotected stones, came from the cones of the spruce 

 tree. He had seen, two years ago, the glossy covering over the 

 leaves of the Liriodendron at flowering time, and found the 

 opening flowers with a large quantity of liquid at the base, and 

 had intended especially to give the matter minute attention the 

 past summer and then report to the Academy ; but his long 

 journey had diverted him. Recently the subject had been again 

 brought to his attention during some experiments in relation to 

 pollinization and cross-fertilization in Platycodon grandifiora not 

 3'et concluded. Cutting open very carefully a corolla just about 

 to expand, the whole inner surface was found to be coated with 

 minute drops of moisture, which, as they gathered in size, streamed 

 down toward the base of the pistil. This liquid was not sweet, 

 but had the taste of lettuce. In the case of the moisture which 

 exuded from the divisions of the perianth in Yucca gloriosa and 

 Yucca arigustifolia before reported, the taste was rather bitter 

 than sweet. He said there was reason for the belief that much 

 of the moisture found at the base of flowers was not the product 

 of " nectariferous glands," which were sometimes guessed at rather 

 than always detected, but was rather the collection from exudation 

 from the petals ; and if so it was a confirmation of Dr. Hoffman's 

 idea of the origin of honey-dew through the surface of the leaf, 

 as we nVight reasonably suppose a modified leaf like the petal of a 

 flower to have some functions in common with the primary leaves 

 from which they sprung. 



AVhat is the object of this abundant exudation of sweet liquid 

 and vliquid of other character from leaves and flowers ? Tlie 

 speaker said we were so accustomed to read of nectar and nec- 

 taries in connection with the cross-fertilization of flowers, that 

 there might seem to be no room for any other suggestion. But 

 plants like' the Thuja and Abie^ were anemophilous, and having 

 their pollen carried freely by the wind, had no need of these 

 extraordinary exudations from any point of view connected with 

 the visits of insects to flowers. In the case of Thuja, Sach had 

 suggested another use : " Tlie pollen-grains which happen to fall on 

 the micropyle of the ovules are retained by an exuding drop of fluid, 



