ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
69 
are distinguished in the structure of the mature testa in the various 
genera, viz. (1) there are true palisade cells; (2) these are replaced 
by isodiametrical cuticularized cells containing crystals ; (3) there are 
no corresponding cells. This last occurs especially in those fruits which 
do not dehisce. The various sections of the genus Polygala are charac- 
terized by special peculiarities in the structure of the testa. When the 
fruit is indehiscent, the mechanical elements are strongly developed in 
the pericarp, while the testa is rudimentary or disappears entirely ; when 
the fruit is dehiscent and still contains mechanical elements, the testa 
is but feebly developed. 
Leaves of Alpine Plants.* * * § — From an examination of the flora of the 
alpine portion of Sweden, Dr. J. R. Jungner classifies the leaves, with 
regard to their form and structure, under the following heads : — Trans- 
piration leaves, covered with a dense felt of hairs, or otherwise protected 
against excessive transpiration ( Salix lanata , Gnaphalium norvegicurri ) ; 
Frigor-leaves, small, crowded, with recurved margins ( Empetrum nigrum , 
Azalea procumbens ) ; Circumpolar light-leaves, found in the highest 
latitudes, erect, very narrow, and commonly cylindrical, protected against 
the j>rotr acted insolation (Juncus trijidus , Air a alpina) ; Snow-leaves, 
growing flat on the snow or on wet ground, generally circular or kidney- 
shaped ( Salix herbacea, Viola bijlora , Betula nana) ; Wind-leaves, lobed 
or incised, protected against violent winds ( Geranium sylvaticum , Banun- 
culus glacialis). Any of these types may be occasionally found remote 
from the conditions in which they originated. 
Spiral Phyllotaxis.j' — In an examination of the phyllotaxis in spiral 
lines which occurs in many genera of Monocotyledons, especially in Pan- 
danus and Cyperus , Herr S. Schwendener finds a constant occurrence of 
larger or smaller divergences in the angle, which can only result from a 
'continuous torsion of the apex of the shoot. 
Tubers of Tacca and Tamus.J — M. C. Queva attributes the forma- 
tion of a tuber to the partial or entire suppression of the growing point 
of the stem, one or two tubers then being formed at the expense of 
axillary buds ; these produce leaves, and finally a flowering stem. The 
tuber of Tamus communis (as also those of Dioscorea sinuata aud altis- 
sima) is the result of a secondary hypertrojfhy, which is limited to the 
dorsal region of the hypocotyl, extending only to the first two internodes 
of the primary stem. 
Root-swellings of Ailanthus.§ — Herr E. Andreas describes the swel- 
lings which often appear on the roots of Ailanthus glandulosa. They 
are of a vegetative, not a parasitic character ; though fungi occur in 
"them, these take no part in the formation or development of the 
swellings. 
Morphology and5 Biology of the Cactace8e.|| — From a study of the 
structure of the organs of a number of different genera of Cactaceas, 
* Flora, lxxix. (1894) Erganzungsbd., pp. 219-85 (3 pis.). 
f SB. K. Preuss. Akad. Wiss. Berlin, 1894, pp. 963-80 (1 pi.). 
+ C.R. Ass. FranQ. pour l’Avancement d. Sci., 1894, pp. 519-27. 551-9 (8 figs.). 
See Bot. Centralbl., lx. (1894) pp. 234, 235. Cf. this Journal, 1894, p. 83. 
§ ‘ Ueb. abnorme Wurzelscliwellungen b. A ilanthus glandulosa ,’ Erlansren, 1894, 
■34 pp. and 3 pis. See Bot. Centralbl., lx. (1894) p. 187. 
|| Flora, lxxix. (1894) Erganzungsbd., pp. 49-86 (17 figs.). 
