536 Brenchley and Jackson. — Root Development in Barley and 
this concentration of the laterals in the upper part of the roots was noticeable 
in all the manurial series. In the early stages of growth the addition of 
superphosphate seemed to bring about considerable development of laterals, 
but in the unmanured and in the nitrate plants laterals were fewer, they 
were less branched, and apparently bore fewer root-hairs than those 
receiving superphosphate. In the unmanured plants this condition remained 
throughout the experiment, but in the plants receiving nitrate the laterals 
became very coarse and were much concentrated in the part nearest the 
grain, giving a crinoline effect. This effect was produced by the formation 
of a large number of extra long laterals along the few inches of root near 
the grain, rather than by the formation of numerous roots practically all at 
one point. The plants receiving superphosphate and nitrate also showed 
this crinoline effect very strongly. At later stages of growth the roots of 
the nitrate and of the superphosphate and nitrate-treated plants had become 
so densely matted together that it was impossible to decide whether the 
crinoline effect was still present or not. At maturity there was certainly 
no such effect observable in the nitrate only plants, for by this time the 
total amount of root system was very much smaller than it had been at 
earlier stages. In the superphosphate and nitrate plants, however, the 
crinoline effect was still observable at the last examination. The plants 
with superphosphate and potash also showed some crinoline effect, but this 
was not as marked as that of the nitrate plants. A noticeable feature in 
the potash series was the thickening and stiffening of the roots near the 
crown, where the laterals also were of a coarser type than elsewhere. This 
stiffening caused the roots to stand well away from the plant, and even 
when they were taken out of water the roots showed no tendency to 
collapse against each other, as they did in plants from all the other manurial 
series. As this did not occur in the, plants receiving superphosphate only, 
it was presumably an effect due to the potash. Again this effect was not 
observed at maturity, when the root system was very much reduced 
in size. 
[b) ‘ White * roots. The plants were first examined eleven days after 
sowing, when the shoots were about half an inch above the soil. Seven or 
eight roots were present, the longest being about 5 in. ; lateral branches had 
not made their appearance, but root-hairs were very plentiful, especially 
near the grain. Seven days later laterals had developed on all the roots, 
and as growth proceeded there was an increase in the number and length 
of the roots and a similar increase in the development of laterals. It was 
not until fpur weeks after sowing that the first ‘ white ; roots made their 
appearance. At this time the shoots of the unmanured plants were about 
11 in. long with no tillers, the main roots being about 15-20 in. One plant 
examined showed a root about J in. long coming from the base of the grain, 
of a much thicker nature than any of the others and of a dead white colour 
