The slit was found in one case to be 3.2 mm. in length, and
it is seated on the line of confluence of the two petioles. The leaf when
it first escapes from the chamber is buried beneath the ground, and now an
upper part of the petiole near the blade becomes arched in the usual
manner. The second leaf comes out of the slit either straight or somewhat
arched, but afterwards the upper part of the petiole,--certainly in some,
and we believe in all cases,--arches itself whilst forcing a passage
through the soil.
* 'Botanical Text-Book,' 1879, p. 22.
[page 81]
Megarrhiza Californica.--The cotyledons of this Gourd never free themselves
from the seed-coats and are hypogean. Their petioles are completely
confluent, forming a tube which terminates downwards in a little solid
point, consisting of a minute radicle and hypocotyl, with the likewise
minute plumule enclosed within the base of the tube. This structure was
well exhibited in an abnormal specimen, in which one of the two cotyledons
failed to produce a petiole, whilst the other produced one consisting of an
open semicylinder ending in a sharp point, formed of the parts just
described.
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