HyYPOCOTYL IN THE GENUS LUZULA. 107 
if we imagine a seed to germinate thus within the remains of the 
perianth and capsule, it seems clear that they cannot be carried 
downward by the root, since they are firmly held by the fixing 
hairs, as had undoubtedly happened in the case of the seedlings 
collected last year. 
No trace of a piliferous layer can be seen throughout the whole 
length of this structure—in some cases more than half an inch in 
length—which separates the leaves from the flower parts which 
had enveloped the seeds, in this year’s seedlings. Moreover, lateral 
roots, when developed upon it later, arise in acropetal succession. 
On seeking an explanation for the difference in growth of the 
two lots of seedlings, I at once remembered that, while last year 
I had sown all the seeds I was observing on the surface of moist 
fibre or other material, this year, owing to dene failures in ger- 
mination, I had had all my seeds sown in the ordinar y way, below 
the surface, in pots of sandy soil. Fortunately, the wiisle of 
the seedlings which interested me had not been removed from 
the pot in which they were growing, and on examination it was 
found that the seeds had been sown exactly as far below the soil 
surface as the hypocotyl had elongated. That this was so, was 
made very clear by the fact that, though some seeds had been 
considerably nearer the surface than others, the hypocotyl had 
only elongated sufficiently to bring the plumule above ground. 
In other words, the elongation was just sufficient to raise the 
embryonic shoot to the surface of the earth. © 
Being anxious to ascertain the subsequent fate of the hypocotyl, 
a number of seedlings were kept growing for a time and examined 
at intervals, It was found that very soon lateral roots began to 
appear, arising from the central vascular cylinder, clearly visible 
in the hypocotyl. The first of these usually appeared about the 
same time as the first foliage leaf began to emerge from the 
sheath of the cotyledon. It was situated, as a rule, in the lower 
half of the hypocotyl, very often quite close to the primary root. 
One by one other similar lateral roots arose above the first, each 
stronger and thicker than that preceeding it; till finally, when 
about the third foliage leaf had appeared, several lateral roots 
arose from the base of the leafy rosette (Figs. 4-7). Very 
soon quite a bunch of these roots had been formed, and the 
hypocotyl, with the roots it bore, began to shrivel. Within three 
