126 BOTANICAL GAZETTE [FEBRUARY 
Symbiosis and saprophytism: D.T. MacDouaat, University of 
Minnesota.—The terms saprophyte and holosaprophyte should. 
be applied to those forms which derive their food supply from. 
organic products directly, without the aid of mycorhiza, tuber 
cles, etc. This category includes numerous bacteria, fungi, and 
but two seed-forming genera, Wullschlegelia, and Cephalan 
thera. The last named has been added by recent investiga 
tions of the author. The extension of the saprophytic capacity 
of seedlings results in the reduction of the seeds, and may 
also be prolonged to include the entire life history of the spor 
phyte. 
Influence of inversions of temperature and vertical air-currems 
upon the distribution of plants: D. T. MacDouaat, University af 
Minnesota.— As a consequence of the rapid radiation from the 
soil and low conductivity of dry air, the lower layers of aif art 
cooled much more rapidly than the upper layers. In broket 
regions the cooled air flows down into the valleys, giving them 
a lower minimum than that at the adjoining hills. The diurnal 
ascending currents give the hills a lower maximum that the: 
valleys. A valley at Flagstaff, Ariz., showed a temperature 15 
to 27° F. below that of an adjoining hill at night, and was 3" 
5° warmer in the day. As a consequence, the average tempel 
ture of the valley will be lower than that of the adjoining hills 
and the temperature of the hills will be more equable than ™ 
of the valley, provided the difference in elevation be less a 
1000". At this and greater differences of height the disturbia 
factors of increased insolation, effect of altitude, and expansi@t 
and compression of the atmosphere come into play. The expt 
sion and cooling of ascending currents of air increase" 
humidity, and thus give certain local ridges and rims 
a comparatively moist atmosphere. According to the 
influence of temperature upon distribution, and supported 
observations-of the writer in the southwest, also by the ™ 
of Professor Townsend, the following conclusions are reac 
(1) Inversions of temperature and resulting air-currents 5° 
minor highlands a much more equable temperature than ajar 
