234 BOTANICAL GAZETTE ‘Sera 
important crop plants whose culture provides employment for tens of millions, 
and whose products constitute the daily food of hundreds of millions of human 
beings. Such a condition is discreditable alike to biological and to agricultural 
science and should not longer continue.” 
In reference to the date palm the following conclusions are reached: It ca 
endure any degree of heat and any amount of dryness in the air, and is even 
favored by hot winds and by a rainless summer. The best sorts can mature only 
in regions having a very long and very hot growing season. It can endure more 
alkali in the soil than any other profitable crop plant, and can thrive on soils 
containing from 0.5 to 1 per cent. of alkali, even when irrigated with brackish 
water containing 0.43 per cent. (430 parts per 100,000) or more of injurious 
alkali. It can withstand without injury accumulations of alkali at the surface of 
the soil that would kill all other crop plants, even those considered to be vey 
resistant to alkali—J. M. C. 
PorsILp5* gives an account of the expedition to Disko Island in 1898. ‘The 
account includes observations on the geology and topography of the island, 
incidental notes on the fauna, and detailed notes on the flora. In conclusioa 
he discusses the southern flora of the island, considering the questions of possible 
relict endemism from a warmer epoch, and migration in postglacial times. 
The upland vegetation consists of lichens and herbaceous plants with very 
few shrubs. Under this category are placed the windy plateaus, the sheltered 
terraces of the trap, the gravelly bottoms and deltas, and the raised sea bottoms. 
The Calluna heath is found on the talus and gradual slopes of the trap, on large 
hills poor in humus, or in depressions rich in water. The tundra is 
as a peculiar formation transitional between the moss-bog and the Calluna heath, 
the transition to one or the other depending upon the water content of the sol, 
Moss bogs are found where water stagnates and is sour, on gneiss, 0 csi 
basalt, and on undrained terraces, where the bog often goes above the ag 
In some cases the moss formation actually forms the climax type after a 
luna, and in comparison is relatively unmixed in its species. 
Halophytes occur along the sea strand. Cyperaceous meadows occur . 
along streams in very flat and moist soil. Dwarf birches and willows Be ea 
found along streams, the former occurring on a somewhat drier soil 
latter. 
when flowe : other ‘ 
ting plants are considered. Mosses, on the ee Sorces 
2 Be Disko til- 
__ * Porsixp, M. P., Bidrag til en Skildring af Vegetationen pa@ pee 35° 
ligemed spredte topografiske og zoologiske Iagttagelser. Medel, 9 
91-308. pls. I-6. 1902, 
