ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 347 



surface only ; the margin is doubly serrate ; a lateral vein of the first 

 order runs into every primary tooth. The aruncoid form of leaf is 

 very widely distributed, occurring in the Rosaceae (Spiraea, Rubus, Rosa), 

 Umbelliferae [Angelica, Chserophyllum, Mgopodium), Compositse (Eupa- 

 torium), and many other orders. They are mostly shade-loving plants 

 with thin leaves. The double serration appears to be a protection 

 against tearing by the wind. 



Position of the Lamina of the Leaf of Grasses.* — Dr. E. Paratore 

 discusses the theory of Duval-Jouve (supported by Darwin) that the 

 semi-torsion of the leaf of many grasses in an adaptation for the pur- 

 pose of protecting the stomatiferous surface of the leaf from too intense 

 light ; and comes to a conclusion different from that of these two 

 observers. The movement which brings about this position of tbe leaf 

 he regards as purely passive, and without relation to the distribution of 

 the stomates on the two surfaces of the leaf. 



Apical Pores of the Leaves of Aquatic Plants, f — Herr P. Wein- 

 rowsky classifies the water-pores or apical openings in the leaves of 

 vi ater-plants under two heads: — In the first group (Sagittaria sagittse- 

 folia, Alisma sparganiifolium and natans, Sparganium ramosum, Stratiotes 

 aloides, Ceratophyllurn demersum, Myriophyllum verticillatum, and several 

 species of Potamogeton), the apical pore is formed by the disorganisa- 

 tion of superficial cells on and immediately beneath the apex of the leaf. 

 In the second group (Callitriche verna and autumnalis, Ranunculus aqua- 

 tilis, Veronica Anagallis), the pore is formed by the absorption of the 

 two guard-cells of water-fissures. Hippuris vulgaris presents a struc- 

 ture intermediate between the two. The leaves of Typha angustifolia, 

 Nuphar luteum, Salvinia natans, Elodea canadensis, Utricularia vulgaris, 

 and Aldrovanda vesiculosa have no apical pores. Their function appears 

 to be to promote the escape of the current of water which circulates 

 through the plant. 



Leaves of Chloranthaceae.l — Herr H. Schulze has examined the 

 structure of the leaves in a number of species belonging to the three 

 genera of this order, Cldoranthus, Hedyosmum, and Ascarina, and finds 

 them to agree in the following general characters : — The presence, in 

 all species, of an ethereal oil or resin, in spherical glands situated in 

 the mesophyll, never in the epiderm ; the presence, in all species, of a 

 branched palisade-parenchyme ; the absence of hairs on the leaves ; and 

 the limitation of the stomates to the under side of the leaf. 



Hairs, Anthocyan, and Extra-nuptial Nectaries of Ailanthus 

 glandulosa.§ — Sig. L. Macchiati describes two kinds of hair in this 

 plant, one of a deep red colour, the other uncoloured. Like the colour- 

 ing matter of the epidermal cells of the leaf, the pigment was deter- 

 mined to be anthocyan. At the base and on the margin of the young 

 leaves are two or more nectariferous glands which constitute an extra- 

 nuptial nectary, the plant furnishing a good illustration of myrme- 

 cophily. The nectar of these glands is greedily devoured by ants, 



* Malpighia, xiii. (1899) pp. 237-51 (1 pi.). 



t Beitr. z. wiss. Bot. (Funfstuck), 1898. 47 pp. and 10 figs.. See Beih. z. Bot. 

 Centralbl., ix. (1900) p. 176. J Beih. z. Bot. Central*)!., ix. (1900) pp. 81-5. 

 § Bull. Soc. Bot. Hal., 1899, pp. 103-12. 



