Igtt] CURRENT LITERATURE 247 
km. from the mainland, this island enjoys many of the features of an insular 
climate. February, the coldest month, has a mean temperature of only 
1°34 C., and the lowest temperatures of the winter seldom exceed —8° C 
This is much milder than the climate of the mainland, but less genial than 
that of the southern coast of England. Notwithstanding the favorable 
temperatures, many plants are injured by the severe and incessant winter 
winds, and by the lack of a protective covering of snow. Kuckuck describes 
his results in detail, indicating the successful culture in the open of a large 
number of species, including such plants as Pittosporum Tobira, Camellia 
japonica, two species of Fuchsia, and various opuntias. Perhaps the most 
noteworthy of them is the fig, Ficus carica, which has been cultivated on 
the island for thirty years, attains a height of 4.5 meters, and matures fruit 
regularly. Kuckuck considers in general that the winds are more hostile 
to plant life than the frosts, and believes that other species might prove hardy 
if they could be given soils better suited to their requirements.—H. A. GLEASON. 
Twining.—NIENBURG?’ has made a detailed study of the nutation move- 
ments of young twining plants in their early stages of circumnutation. He 
believes that all the circumnutation and twining movements can be explained 
by the joint action of autonomic nutation and negative geotropism. He also 
believes that he has entirely disposed of NoLt’s conception of lateral geotro- 
pism. A careful analysis of his results, however, shows that lateral geotropism 
will also explain all movements he describes, with the possible exception of 
one on the centrifuge. The strongest evidence for NoLL’s conception was 
gained from the use of the centrifuge, and now with a slight alteration of the 
position of the plant NrENBURG obtains results on this instrument that seem 
to disprove Nout’s conception. NIENBURG’s centrifuge experiments have 
their main value, however, in showing the need of further centrifuge snes 
in this field—Wititam CROCKER. 
Amphibious polygonums.—A recent paper very plainly shows that exten- 
sive experimental cultures will be necessary before the taxonomic and ecological 
relationships of the various species of Polygonum can be settled. NreuwLAND* 
distinguishes at least three closely related species of this interesting genus 
which exhibit both an aquatic and a terrestrial form, but adds no experimental 
data to our present scanty fund. The species described vary so mu 
response to varying conditions of habitat that it seems possible that all these 
forms, with intermediate gradations, might be produced from the same stock 
by careful methods of culture. An interesting historical résumé of the litera- 
37 ek oe Die Nutationsbewegungen — Flora 
102; I17-1 46. 
38 ies: J. A., Our amphibious Persicarias. Amer. Midland Naturalist 
2:1-24. IQII 
