430 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Leafy branches of Cupressineae.* — According to Herr P. Klemm, the 

 principal differences in the anatomical structure of the branches of 

 Cupressineae depend upon whether they are I'adiar, bilateral, or dorsiventral, 

 a point which is apparently dependent largely on the illumination. The 

 epidermal cells have a row of jjores on their side-walls, the pores of adjacent 

 cells usually corresponding. The cuticle is often covered with a coating of 

 wax, and has usually crystals of calcium oxalate imbedded in it. Besides 

 the central and perij)heral stereome, there are also often steroids in the 

 parenchyma, which are generally idioblasts. The palisade-parenchyma is 

 on the morphologically under side of the leaf ; the cells of the abducting 

 tissue are elongated in the longitudinal direction, those of the conducting 

 and assimilating tissues in the transverse direction. The conducting system 

 presents no special peculiarities. The stomata are usually on the non- 

 illuminated side, where there is no palisade-parenchyma ; their structure 

 is quite of the ordinary kind. The resin-receptacles are either entirely 

 imbedded in the parenchyma, or they are adjacent to the epidermis, causing 

 the formation of channels or pits. 



Transparent Dots in Leaves, especially of Connaracese.t — Dr. L. 

 Eadlkofer describes the various points of structure which give rise to tho 

 appearance of more or less transparent dots in species belonging to a large 

 number of different natural orders. Those belonging to the Connaracese, 

 especially tho genera Connarus and Bourea, are described in detail, and the 

 value of the character for taxonomic purposes is discussed. A new genus 

 Pseudoconnarus is proposed, formed out of Connarus fecundus, and distin- 

 tinguished from the typical genus by the absence of dots on the leaves. 



Foliar Lenticels.| — In investigating the large lenticels on the leaves 

 of Camellia japonica. Prof. A. Borzi finds that they are essentially connected 

 with the stomata, which are of two kinds. At the time when the young 

 leaves first emerge from the bud, there is no visible trace of lenticels. 

 There are two different sets of stomata, formed at different periods, the 

 first set controlling the respiration during the earlier, the second set during 

 the mature period of the leaf. The epidermal cells from which the second 

 set is formed show scarcely a trace of segmentation at the time when the 

 first set are mature. As soon as the first set become useless by the 

 formation of the second set, their guard-cells are transformed into a corky 

 cushion ; and at the same time the subjacent cells of the mesophyll divide 

 by tangential septa, and their walls become suberized. In this way is 

 formed a true lenticel. 



The lenticels on the petioles of Aralia papyrifera and Sieholdii have the 

 form of corky emergences, but present no special points in their structure 

 or mode of origin. 



Ochrea of Polygonace8e.§ — According to M. Colomb the ochrea of the 

 PolygonacesB is a comi)ound structure, composed of two portions, one 

 opposed to the leaf, which is its sbeath, the other situated in its axil, 

 and detached from the petiole, which is a ligule. A similar structure 

 occurs in the stipules of Ficus and Magnolia. 



Epidermal Glands containing an Ethereal Oil.|j — Herr J. Behrens 

 describes the well-known multicellular glandular hairs of Pelargonium 



* Pringwluiiu's Jahrb. f. Wiss. But., xvii. (1886) pp., 499-541 (4 pis.). 



t SB. K. Bayer. Akad. Wiss., xvi. (18SC) pp. 299-378. 



t Malpighia, i. (1886) pp. 219-27 (1 pi.). 



§ Bull. Soc. Bot. France, viii. (1886) pp. 506-7- 



J! Ber. Deutseh. But. Gesdl., iv. (1886) pp. 400-4. 



