W50 

 (leaf 2) 



The production of flower stalks and seeds continues for an un- 

 usually long period. The lower flowers appear early in the summer 

 and are the first to unfold ; as the season advances, there is a gradual 

 succession in flowering toward the top of the cluster (raceme). The 

 uppermost flowers are usually still in bud or in full bloom while the 

 lower ones have developed mature seedpods (capsules), or even 

 mature seeds, so that flowering continues in some localities for about 

 3 months, from, about June to August. Fireweed produces a great 

 abundance of seed which usually matures from mid-July to late 

 September. When fully ripe, the long slender seedpods split into four 

 divisions and liberate a great number of very small seeds, each pro- 

 vided with a tuft of silky hairs which enables them to be carried far 

 and wide by the wind, a light breeze being sufficient. During the 

 period of greatest seed dissemination in areas where fireweed is com- 

 mon, the air is filled with the light, cottony seeds, which are soon 

 widely distributed. But few cut-over and burned-over areas escape 

 their invasion. The seeds find ideal lodgement in new burns where 

 the ashes apparently stimulate germination and growth, but their 

 viability is evidently not very high, Sampson 2 having found that in 

 1908 and 1909 it averaged 21.5 percent in the Blue Mountains of 

 Oregon. The seeds produced early in the season were from 10 to 12 

 percent higher in viability than those maturing later. 



Fireweed is quickly established and usually forms a cover within 

 two seasons which overtops or even excludes other plants and shrubs. 

 Notwithstanding its great seed-producing capacity, this species soon 

 appears to propagate mainly from underground rootstocks which 

 bud along their length and send up new stems. Ingram (op. cit.) 

 found that a definite rootstock is formed the first season, during 

 which time it grows 4 to 6 feet in extent, and the above-ground part 

 of the plant usually becomes 2 to 3 feet tall. The new growth above 

 ground and the older portion of the rootstock die each succeeding 

 year. In one instance, a 4-year-old rootstock was traced for a dis- 

 tance of 20 feet and about 56 undeveloped buds were counted along 

 it, although the average number is probably less. 



Ingram concluded that the ability of this plant to withstand com- 

 petition is probably limited because, with the advent of shrubby 

 species as reforestation proceeds, conditions become too unfavorable 

 for its continued growth. It subsequently declines in quantity and 

 size until, after 8 to 12 years, it comprises but a minor part of the 

 vegetation. 



Fireweed is well known as a nectar-producer, and bees and other 

 insects are attracted by its flowers. In the coastal regions of Oregon 

 and Washington apiarists follow the logging operations, moving 

 every 5 to 7 years to newer cut-over areas where fireweed is most 

 abundant. 



* Sampson, A. W. IMPORTANT RANGE PLANTS : THEIR LIFE HISTORY AND FORAGE VALUE. 

 U. S. Dept. Agr. Bull. 545, 63 pp., illtis. 1917. 



