Nov. i6. 1914 Revegetation of Range Lands 109 



on hillside terraces formed by the trailing of sheep, and, in fact, every- 

 where that its seed is developed. In favorable situations i square meter 

 of surface showed as many as 700 seedlings of porcupine grass in the spring 

 of the year. This unusual aggressiveness is not due, as might be expected, 

 to exceptionally strong seed habits, but chiefly to the morphology of the 

 scale, or lemma, which closely envelops the seed. The scale is very 

 rigid, with an awn about lyi inches long protruding from the apex. At 

 maturity this awn is tightly twisted, as shown in Plate XV, figure 2, 

 but when moistened it untwists vigorously, causing the bent, needle-like 

 point at the lower end of the scale to bore into the ground, the stiff, 

 backward-turning hairs holding it in the earth when once started. The 

 repeated twisting and untwisting of the awn with variation in the mois- 

 ture finally results in the complete burial of the seed prior to the germina- 

 tion period. 



Thus, if the seed of the valuable forage species is not planted by arti- 

 ficial stirring of the soil, undesirable species, such as white foxtail, may 

 become established at the expense of the valuable range plants. 



GROWTH AND ESTABLISHMENT OF REPRODUCTION OF FORAGE PLANTS 



The production of a seed crop of high viability does not necessarily mean 

 any material increase in the forage stand. The seedling plants are often 

 seriously injured or destroyed in the fore part of the grazing season by 

 low temperature and lack of soil moisture. Certain plauts are not sub- 

 ject to as serious injury as others, and so the ultimate stand may consist 

 of a single species. The growth and vitality of reproduction will be dis- 

 cussed under three heads: (i) "Development and loss of forage seed- 

 lings during first year;" (2) "Loss of forage seedlings during dormant 

 period following first year;" and (3) "Growth and loss of forage seed- 

 lings during second and subsequent seasons." 



DEVELOPMENT AND LOSS OF FORAGE SEEDLINGS DURING FIRST YEAR 



During the first season of growth in the Hudsonian zone, approxi- 

 mately ID weeks long, the seedlings do not grow tall enough to produce 

 forage, though the young plants are sometimes cropped to a limited 

 extent in the autumn. The height attained by mountain bunch-grass, 

 as well as the root development, is shown in Plate XV, figure 3. It will 

 be seen that the depth of the root slightly exceeds the height of that por- 

 tion of the plant above ground. This plant represents about the average 

 development of a forage seedling on well-drained and drier situations 

 during the initial year of growth. On the lower elevations, owing to 

 the longer growing season, the seedling plants usually attain much greater 

 development than the one shown. 



Observations extending over five successive seasons show that in nor- 

 mal years the low temperatures characteristic of the Hudsonian zone 

 are responsible for considerable loss of seedlings during the first year of 

 G2697°— 14 2 



