ZOOLOGY AND BOTANYj MICKOSCOPY, ETC. 407 



of the " moon-flower," Ipomsea hona-nox. This is characterized by two 

 features not hitherto recorded: a fine velvety coating consisting ap- 

 parently of rigid filaments adherent to one another, about 1/4500 of an 

 in. in length, arising directly from the surface of the extine ; and two 

 kinds of papillae. Of these the larger club-shaped processes proceed 

 from the extine ; but the smaller conical ones are processes of the intine 

 protruding through the extine, a structure not previously observed in 

 pollen-grains. The velvety covering of the grains was observed in several 

 other species of Ipomaea and Convolvulus ; and the conical intinal processes 

 protruding through the extine also in the pollen-grains of the " morning 

 glory," Ipomeea purpurea. 



Fruit-scales of Abietineae.* — From the examination of a number of 

 abnormally developed cones of the larch, Dr. J. Velenovsky draws the 

 conclusion that in the Abietinese the fertile scale is composed of two 

 leaf-scales, though it does not follow that this is also the case in the 

 other sub-orders of the Coniferae. The double scale of the cone of 

 Abietineas can be compared to the double leaf of Sciadopitys, this 

 doubling being a very common phenomenon in the vegetative organs of 

 the Coniferae. Some of the cases were prolonged above into shoots 

 bearing leaves, many of which had ordinary leaf-buds in their axils. In 

 some of these buds all the scales have become fleshy, and each bears on 

 its under side a rudimentary ovule, the whole closely resembling the 

 fructification of a Cycas. All intermediate forms are to be met with 

 between these structures and normal buds. 



Seeds of Nymphseacese.t— Pursuing his investigations on this 

 subject, Prof. G. Arcangeli novsr describes the structure of the seeds of 

 NympJisea alba and Nuphar luteum. In the white water-lily the ripe 

 seeds have a very short funicle, and are surrounded by a copious white 

 aril, within which is a well-differentiated double integument. The seed 

 itself is composed of three parts, the embryo, the albumen (endosperm), 

 and the perisperm. Of these the first and the third occupy by far the 

 largest portion of the seed, the endosperm consisting of a single layer 

 of cells in direct contact with the surface of the embryo. The cells of 

 the embryo and endosperm are full of albuminoid and oily substances, 

 those of the perisperm, on the other hand, of starch. In the yellow 

 water-lily the seeds have a longer funicle, and no true aril, but the 

 integument again consists of two distinct coats. The endosperm is 

 somewhat more developed than in Euryale and NympTisea, consisting of 

 from two to four layers of cells. As in the latter genus, the perisperm 

 is by far the largest constituent of the rip 3 seed, and is the principal 

 reservoir of the amylaceous food-materials, the albuminous and oily 

 substances being stored up in the cotyledons and the endosperm. 



Bract in Tilia.J — Mr. T. Meehan states that the small leaf adherent 

 for some half its length to the common peduncle in the linden tree is 

 known as a wing-bract. The use of the dried bract as a wing to aid in 

 the distribution of the seed can scarcely be its sole purpose. But the 

 lifting power of the growing bract is apparent ; and, though it is difficult 

 to understand how the adaptations are of much use to the plant, it will 

 be perhaps more difficult to believe that the adaptations have been made 



* Flora, Ixxi. (1888) pp. 516-21 (1 pL). 



t Nuov. Giorn. Bot. Ital., xxi. (1889) pp. 122-5, 138-40. Cf. ante, p. 250. 



X Bull. Torrey Bot. Club, xv. (1888) pp. 316-7. 



2 F 2 



