ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 1011 



Myrtacere, CEnothereaa, Convolvulaceae, and certain ligulifloral Com- 

 positae, the internal liber has neither the same structure nor the same 

 origin as that of the normal bundles. 



With regard to the connection between the anatomical structure 

 of the stem and the mode of life of the plant, M. Herail concludes 

 that the unity in the plan of structure of the stem persists through 

 all the modifications or variations to which that organ is subject. 

 The anomalies of structure are independent of the life of the plant ; 

 the causes of these anomalies cannot yet be determined. 



In respect of variations in the histological structure of the various 

 elements which compose the tissues : — the composition of the wood is 

 independent of the mode of life, but, as a general rule, the diameter 

 of the vessels is larger in twining or climbing plants than in those of 

 ordinary habit. The greater or less development of the ligneous 

 parenchyma and of the medullary rays is in no way dependent on the 

 mode of life of the plant. The tegumentary apparatus is that which 

 is least affected by the conditions of vegetation ; its structure is 

 generally uniform throughout a family, not varying according to 

 whether the plant is climbing or erect. 



Value of the Structure of the Wood of Dicotyledons for Classi- 

 fication.* — Herr H. Solereder has examined the structure of the wood 

 in 138 orders of Dicotyledons, for the purpose of obtaining an answer 

 to the question whether, in general, characteristic features are constant 

 in the structure of the wood for larger or smaller circles of affinity. 

 He answers the question in the affirmative for families, tribes, genera, 

 and even species. The characters relied on are the distribution of 

 the various lignified elements in the different parts of the stem, and 

 the nature of the thickenings of the walls of the vessels themselves ; 

 but only woody plants were examined in the various orders. 



Tubercles on the Roots of Papilionaceae.t — Herr F. Schindler 

 has reinvestigated the structure of the tubercles on the roots of Tri- 

 folium pratense, Vicia villosa, Anthyllis Vulneraria, Ornithoims sativus, 

 and Phaseolus vulgaris, and reasserts his former interpretation J that 

 they are normal organs, localities for the fresh formation of albu- 

 minoids to be consumed in other parts of the plant. 



Causes of the various kinds of JEstivation.§ — Herr K. Schu- 

 mann classifies the various kinds of torsion which occur in the deve- 

 lopment of petals under two heads, constant and inconstant. In con- 

 stant torsions all the different members of a whorl have similar 

 positions, or the corresponding members originate in the same way. 

 They may be either isotropous or anisotropous. To the latter kind 

 belong the quincuncial and decussate imbrications ; to the former, 

 when all the members have similar positions, the valvate and the con- 



* Solereder, H., 'Ueb. d. systematisehen Werth der Holzstructur bei d. 

 Dikotyledonen,' 204 pp., Miinchen, 1885. See Bot. Ztg., xliv. (1886) p. 506. 



f Heimtber^'s Journ. f. Landwirthsch., xxxiii. pp. 325-36. See Bot. 

 Centi-albl. , xxvii. (1886) p. 108. 



% See this Journal, iv. (1884) p. 588. 



§ Ber. Deutsoh. Bot. Gesell., iv. (1886) pp. 53-68 (7 figs.). 



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