986 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Super-endodermal Network in the Root of Rosaceae.*— M. P. van 



Tieghem has already described the structure of the cortical layer of the 

 young root in Coniferse and CrucifersB in contact with the endoderm, which 

 is furnished with a network of lignified thickenings. In this paper he 

 continues this work with the Rosacese. 



In a young root of the pear, each cell of the super-endodermal layer 

 has a lignified thickening-band in the middle of the radial and transverse 

 walls. This band projects towards the interior in a semicylindrical form, 

 and incloses a rectangular cell. From each side of the common partitions 

 the two bands correspond exactly, and unite to form one thick cylindrical 

 band. The longitudinal and transverse bands constitute a network with 

 rectangular meshes, and this forms a strong support for the young root. 



Of forty genera of Eosaceae examined by the author, thirty possess a 

 super-endodermal network, and ten are destitute of one. These ten genera 

 are confined to tjie three tribes PotentillesB, Poterieae, and Quillajaeae ; but 

 the first two also contain genera which possess a network. Among the 

 Poteriege, for instance, the Sanguisorbese have a network, while the Pim- 

 prenellesB (^sic) are destitute of one. Among the thirty genera of Rosaceaa 

 which possess a network, various slight modifications are to be found ; these 

 the author describes in detail. 



In conclusion, it will be seen that there are now three great families of 

 plants in which the young root is provided with a super-endodermal network 

 — the Coniferse, Eosaceae, and Cruciferae. In the latter case only the 

 meshes of the network are reticulated. 



Anatomical structure of the wood of Leguminosae.t — Herr A. Saupe 

 finds that the separation of the order Leguminos^ into the three suborders 

 Papilionaceae, Caesalpiniese, and Mimoseae, does not correspond to any 

 general differences in the structure of the wood. All the species of parti- 

 cular tribes do, on the other hand, present common characters in this 

 respect, as, for example, in the tangential section of the medullary rays. 

 This is especially the case in the tribes Genistete, Dalbergieae, and Galegese. 

 Certain nearly related genera exhibit also a more exact resemblance in 

 their microscopical characters, as, for example, Oymnocladus and Gleditschia 

 among Caesalpinieae, and Colutea, Halimodendron, and Garagana among 

 Papilionaceae, and especially Wistaria and Bohinia, which is the more 

 remarkable from the difference in habit of these genera. Only rarely could 

 the histological character of the wood be used in the discrimination of 

 species, but this occurs in the genera Cassia, Cercis, Podalyria, and 

 Sophora. The climbing Acacia sarmentosa agrees altogether in the struc- 

 ture of its medullary rays with the rest of the genus. 



(5) Structure of Organs. 



Formation of Roots in Austral Coniferse.| — Prof. S. Berggren describes 

 a structure of the roots peculiar to certain Coniferas from the southern 

 hemisphere. In Podocarpus there are formed, along all the younger 

 branches of the roots, two or three moniliform rows of globular or elliptical 

 secondary roots, of constant length in each species, varying in different 

 species from • 25 to 2 mm. They consist, for the larger part, of spongy 

 cortical tissue, the cell-walls of which have spiral or reticulate thicken- 

 ings, which prevent their shrivelling up when dry. The function of these 

 peculiar bodies appears to be the same as that of the aerial roots of 



* Bull. Soc. Bot. France, xxxiv. (1887) pp. 221-3. 



t Flora, Ixx. (1887) pp. 259-68, 275-82, 295-316, 323-35. 



i SB. Bot. Verein Lund, March 17, 1887. See Bot. Oentralbl., xxxi. (1887) p. 257. 



