J^BKUAET 17, 1911] 



SCIENCE 



261 



The habit of these two aroids in producing from 

 2-5 inflorescences in excess of the number they 

 are capable of maturing each year is to be ex- 

 plained in the light of their tropical origin and 

 in their previous more southerly range. 

 Some Effects of Severe Freezing upon, Vegetation 



in a Condition of Active Growth: F. K. BuT- 



TEBS and C. 0. Rosendahl. 



On the night of April 15, 1910, the temperature 

 at Minneapolis fell to 27° F., and a week later to 

 19° F. with a high wind. At the time of these 

 frosts vegetation was in an advanced state, many 

 trees were in full leaf, and nearly all others in 

 active growth. Observations were made upon 

 about seventy species of woody and herbaceous 

 plants. It was found that besides the injury due 

 directly to cold, much mechanical injury resulted 

 from loss of turgidity in succulent young shoots 

 during the early stages of freezing, and from the 

 extreme brittleness of hard frozen leaves and 

 twigs which the wind snapped off in great num- 

 bers. The second freeze injured many plants 

 which were not hurt by the first one. About 42 

 per cent, of woody species lost practically all 

 their foliage, only about 10 per cent, were rela- 

 tively uninjured. Mature leaves and those just 

 unfolding from the bud were less injured than 

 half-grown leaves of the same plant. In about 60 

 per cent, of the species the twigs of the new 

 growth were killed or severely injured. In about 

 15 per cent, the twigs of the past season's growth, 

 and in a few instances older twigs, were injured. 

 Flower buds were somewhat more tender, open 

 flowers and fruits much more tender than vegeta- 

 tive parts. Damage to native herbaceous plants 

 was mainly mechanical, and relatively slight ex- 

 cept in the case of open flowers and fruits. A 

 few weeks afterwards herbaceous vegetation ap- 

 peared normal while woody plants had just begun 

 to recuperate. The most usual types of recupera- 

 tion in trees and shrubs were: (1) when the 

 twigs were uninjured and the terminal bud intact, 

 this often made a further growth bearing a new 

 crop of leaves; (2) when the outer parts of the 

 new twigs were destroyed while the basal pans 

 remained intact, lateral shoots often arose from 

 the leaf axils of these uninjured portions either 

 with or without the intervention of scaly buds; 

 (3) many latent buds started into growth upon 

 the woody twigs, sometimes upon those several 

 years old. In some eases all these methods of 

 recuperation appeared in the same plant. 

 Color PJtotographj/ in Botanical Work: Fkancis 



Ramalet. 



Botanists can make use of the new color pho- 

 tography especially in studies of ecology and plant 

 breeding. Many features of vegetation are 

 brought out much more clearly than by ordinary 

 photography. Thus, a moor with scattered shrubs 

 or a lake-margin surrounded with belts of dif- 

 ferent plants can be well shown. In plant-breed- 

 ing experiments the appearance of the different 

 hybrids and extracted forms can be reproduced 

 with much faithfulness. Colored plates from 

 books are easily reproduced upon lantern slides. 

 The exposure required is about 200 times that for 

 an extra rapid isochromatic plate. Hence no 

 " snap shots " can be taken, but if the light is 

 good there need be no difficulty in securing good 

 results. Development can be carried out in an 

 ordinary dark room. The solutions used are in- 

 expensive and easily prepared. 

 Respiration (CO^ Production) in Air, in Nitrogen 



and in Hydrogen: B. M. Duggab and Geobqe 



R. Hill, Je. 



The experiments reported give data respecting 

 the rate, continuance and decline of anaerobic 

 respiration (CO2 production) in nitrogen and 

 hydrogen as compared with aerobic respiration 

 under otherwise similar conditions. The plant 

 materials used were slices of sugar beet and 

 germinating seed. Special attention is also drawn 

 to the importance of an available nitrogen supply 

 for other physiological purposes. 

 The Flora of the Olympic Peninsula, Washington: 



Albert B. Reagan. 



The Olympic peninsula in northwest Washing- 

 ton comprises a wide coastal strip bordering 

 on the Pacific Ocean, the Strait of Juan de Fuca 

 and Puget Sound, surrounding a totally isolated, 

 central high area termed the Olympic Mountains. 

 These occupy an eroded domed area in the east 

 central part of the peninsula, with a western limb 

 extending in declining altitude to Cape Flattery. 

 The peaks in the central area range from 6,000 

 to 8,130 feet in height. Mount Olympus being the 

 highest peak. The domed surface causes a radial 

 drainage in all directions, but the larger streams 

 flow into the Pacific. 



This peninsula with its lofty peaks stands first 

 in the path of the moisture-bearing southwesterly 

 winds from the Pacific, hence the precipitation is 

 great; at the coast it is usually rain, in the 

 mountains snow. The precipitation averages 40 

 inches north and east of the mountains; west of 

 the mountains at an elevation of 3,000 feet, about 

 80 inches; and in the Pacific and upper-Strait- 

 Flattery region, 100 tr> lOQ inches. Th« climate. 



