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SUMMARY OF CURRENT RESEARCHES RELATING TO 
and his results are not altogether in accordance with those of Scott and 
Brebner.* * * § He states that the phenomenon is not due to the secondary 
formation of a complementary cambium, but to a gradual resumption of 
the normal function. The cambium-layer, notwithstanding its frequently 
strong sinuosities, remains continuous, but becomes unilateral in places, 
in a similar way to a periderm, which forms bark only, and not 
phelloderm, in the centripetal direction. 
Monocotyledons with Secondary Growth. f — M. J. H. de Cordemoy 
enumerates the comparatively few cases in which this phenomenon is 
known in Monocotyledons : — In the Aloinese and Draceeneae among 
Liliaceae ; in Agave, Fourcroya , and Grinum among Amaryllideae ; in 
Aristea corymbosa among Irideae ; and in the roots of Dioscoreaceae. 
The secondary tissue is composed of parenchyme and tracheid-vessels. 
The presence of this tissue indicates the highest type of Monocotyledons, 
and is a step in the passage to Dicotyledons. 
Formation of Callus in Cuttings. J — Herr H. Tittmann has made a 
series of observations on the formation of callus in cuttings of woody 
plants (chiefly Populus nigra and pyramidalis ). If the cutting have 
two cut surfaces, he finds the callus to be formed equally on both when 
placed in similar conditions. The process is simply traumatic, and is 
independent of the action . of light or of gravity. A polarity is sub- 
sequently developed in erect cuttings, causing the formation of shoots 
at one end, roots at the other. If inverted, the basal callus may be 
induced to form shoots, while the apical callus does not form roots. 
Under unequal conditions of the two ends of the cutting, callus may 
be produced at one only. If a cutting is ringed, each portion behaves 
like an unringed cutting ; and they cannot again be united into a single 
cutting unless the continuity of the bark is restored. 
Anatomy of the Santalaceae.§ — From an examination of 21 out of 
the 28 genera of Santalaceae, Herr M. Behm derives the following general 
anatomical characteristics of the order: — The vascular bundles are col- 
lateral ; the walls of the vessels which are in contact with the paren- 
chyme of the medullary rays usually have bordered pits, as also has 
the xylem-prosenchyme ; there are no mucilaginous epidermal cells in 
the leaf ; the guard-cells of the stomates have almost always, right 
and left, a pair of parallel companion-cells ; there are no glandular hairs 
or secretion receptacles ; while groups of silicified cells, and single 
crystals, or clusters of crystals, are common. The genera Champereia, 
Myzodendron, and Grubbia present several abnormalities in their anato- 
mical structure. 
Anatomy of the Caprifoliaceae.|| — Dr. L. Linsbauer describes the 
anatomical structure of a number of species of Caprifoliaceae, which 
order he divides, from morphological and anatomical considerations, 
* Cf. this Journal, 1890, p. 199. 
f ‘ Rech. sur les Monocotyledones a accroissement secondaire,’ Lille, 1894, 108 pp. 
and 3 pis. See Bot. Centralbl., 1895, Beib., p. 89. Cf. this Journal, ante , p. 67. 
X Jahrb. f. wiss. Bot. (Pfeifer u. Strasburger), xxvii. (1895) pp. 164-95. 
§ Bot. Centralbl., Ixii. (1895) pp. 65-74, 97-107, 129-39, 161-70, 193-210. 
|| Verhandl. Iv. K. Zool.-bot. Gesell. Wien, xlv. (1895) pp. 43-68 (1 pi.). 
