918 SUMMARY OF CURRENT RESEARCHES RELATING TO 



The fronds are developed in connection with the central bundles in 

 the phyllophore. In regard to the origin of the bundles, it is 

 sufficient at present to say that they originate at the apex of the 

 phyllophore, and are developed in it, with it, and as a part of it. 

 von Mohl and Mirbel maintain that these bundles grow up into the 

 phyllophore; Gaudichaud, that they grow downward from it, from 

 the frond bases; von Martins, that they grow both up and down; 

 while the author maintains that they are perfected in all directions at 

 the same time, though the lateral growth continues to a certain extent 

 after the longitudinal growth has ceased, and that they can no more be 

 said to grow upward or downward than it can be said of the bones of 

 the body that they grow outwards into the limbs. It is true that the 

 general lengthening of the bundles takes place at the superior end, 

 but there is a growth besides this. At the first appearance of the 

 fronds at the apex of the phyllophore, the fibro-vascular bundles are 

 already connected with them, and just as intimately as they are in the 

 perfectly developed frond. The internodes at this point are very 

 short, but the bundles are the same in number, and have exactly the 

 same connections, direction and relation to each other that they have 

 in later life. But in the perfected frond we find them larger, longer, 

 and harder, and in the perfect stem the internodes are longer, the. 

 stem and bundles larger, while the whole plant has grown both longi- 

 tudinally and laterally. 



Honey-glands of Cruciferse.* — J. Velenovsky has examined the 

 honey-glands in about 170 species of CruciferaB, and finds them only 

 of subordinate use in classification ; they are generally related to the 

 habit of the plant, and the structure and form of the fruit. As a 

 general rule, though not without exception, their size is in proportion 

 to that of the flower. While the lower glands are never absent, 

 though sometimes very small and almost rudimentary, the upper 

 glands are not unfrequently entirely wanting. 



Resin-deposits, f — T. Posewitz has investigated the mode in 

 which the enormous deposits of resin in Borneo are formed. It 

 is produced chiefly by trees belonging to the Abietinese, Burseracese, 

 and Dipterocarpe^, the resin falling from the branches in large 

 lumps, which become mixed with mud and transported by heavy rains 

 to the neighbourhood of the sea. The remains of animals are found 

 abundantly inclosed, both of insects and of other larger animals, land 

 or marine, picked up during their transport. The author compares 

 this with the modes of formation of peat and of amber. 



Distribution of Food-materials in the Plant,+ — Berthelot and 

 Andre find that insoluble mineral substances accumulate in the leaves 

 and inflorescence in preference to any other part of the plant, the 

 leaves being the termination of the circulation of fluids ; they amount 



* SB. K. Bohm. Gesell. Wiss., vi. (1884) (5 pis.). See Bot. Oentralbl., xix. 

 (1884) p. 9. Cf. this Journal, iii. (1883) p. 239. 



t Foldtani Kozlony (Buila-Pest) xiii. (1883) pp. 409-12. 

 X Comptes Rendus, xcix. (1884) pp. 428-31, 



