10 March, 1916.] Variations in Plants from Same Head of Wheat. 169 



sixth row from the top, and that the average rate of germination de- 

 creases towards base and apex of the head. It is worthy of note that in 

 planting out the grains in plots, none should be planted at all close to 

 the edge of the plots, otherwise an increased delay of germination may be 

 stiown by such grains, which is due to physical causes unconnected with 

 differences in thei grains themselves. 



The heads used were from a second generation cross of Federation $ 

 X Bayah ? . When the grain was ripe, the plots (thirteen in all) were 

 examined for signs of individual variation in plants from the same head. 

 There were no noticeable differences in the straw, flag, or in the basal 

 parts of the heads. The tips of the heads varied, however, from some- 

 what tapering ends with a few distant sterile spikelets to blunter ends 

 tipped with awns up to \\ inches long. The majority of the heads were 

 awnless, the ratio being not in a simple Mendelian one, but very nearly 

 in the proportion of 5 : 1. In three out of thirteen plots every head was 

 awnless. In seven plots the longest awn at the tip of the head did not 

 exceed ^-inch, and the awns were confined to the extreme tip or upper 

 third of the head. In the remaining three plots, odd plants from various 

 parts of the head developed awns up to \\ inches long, becoming shorter 

 basally, and being always absent in the lower half of the head. All 

 gradations between these extremes were shown, and, in addition, a 

 similar but less pronounced range of variation was even shown in a few 

 cases between heads stooled from the same grain. 



Apparently, in this case the awned and awnless characters are not 

 sharply defined morphological units capable of simple Mendelian inheri- 

 tance, but are capable of an indefinite range of variation without any 

 distinct line of demarcation, except such as may be made by an observer 

 working upon a preconceived idea. In any case, it may be worth while 

 to test the exact hereditary transmission of the awned and awnless char- 

 acters more fully in a variety of cases. 



POTASH FROM SEA-WEED. 



Thc> Unit<?d State.> Department of Agriculture has made a thorough 

 inquiry into the possibility of using seaweed as a source of potasii for 

 the purposes of cultivation. It is known that some of the seaweeds are 

 rich in potash. Macrocystis contains about 2A per cent., and therefore 

 the main question to }>e resolved is the cost of production. By the i>i- 

 troduction of a machine, I'un on the principles of a harvester, the kelp 

 is harvested in barges at a cost of half a dollar a raw ton. Di;ying in 

 hot-air ovens is estimated to cost a dollar per dry ton. When dry the 

 kelp is brittle, and may be ground readily. From 1,000 tons of wet 

 kelp 86 tons of dry kelj) are obtainable, and tliis contains 16 tons of pot- 

 asii, and a ton and three-quarters of nitrogen. If nii.xed with fish waste 

 manure, it becomes, by the addition of phosphorus from tlie latter, a 

 "perfect" artifirial manure. Estimates of cost and price obtainable 

 indicate that there is a fair margin for profit. 



