468 P. W. CLAASSEN 
TABLE 2. MEASUREMENTS OF THE SEEDS OF TYPHA LATIFOLIA 
Specimen | Length Diameter 
(millimeters) | (millimeters) 
1 Lae eer ects paar ad tceion eh RSTn a ee rae c ens in Matera aie oa lah 1.50 0.29 
Vee RSP ei Ath eT a 5 Ne SRE ey TE Aes Shes 1.21 0.25 
BIN Ace ag ie een te enna tien Te ree pee hie ue ee ER aed ote 1.42 0.28 
TAL AS BeSeSiS acter: See oeU Oe Pon eae Ole UR MRE As oe Lea ee WEG Sat eee eae 1.35 0.28 
Biel LEU Pe ee pe ee ere ot eee ch ok Blea ae al ogee 1.42 0.37 
(CP eM caesarean mane ts 509 FS. gh mas ations, ca Be er 2 3) 1.05 0.28 
Tihs SACS OB) Se See CeR eee an hy ASR eae aos ON ar eee oer 1.42 0.37 
SiS a pe keos oes SR a Oe ea a 1.42 0.37 
OS FEE a Seat Rtas a aR tas Pn aes ee Bea ey ate ete 1.45 0.28 
LO Reo eerie ee ei eee sD ainda ee ule ee ne ene camer 115 0.30 
UN (eh Uex ene os ae ieee eee or Napa Oe GOR ee MIEN ae ote 1.339 0.307 
When germination begins, the cotyledon lengthens and pushes out 
through the trap door. Sometimes the cap is carried away on the tip 
of the developing embryo, but more often it remains attached as if by a 
hinge to the seed. The embryo, immediately after emerging from the 
seed, turns downward toward the bottom of the dish. Growth is very 
rapid. Hardly has the embryo come out of the seed before the epidermal 
cells near the tip begin to send out slender root-hairs, which help to 
fix the plant tothe bottomsoil. The other end of the embryo, or cotyledon, 
remains In the seed, absorbing the reserve starchy material, the only food 
of the young, developing embryo (Plate XX XIX, 5). When the embryo 
has become about twice or three times the length of the seed, the growing 
tip pushes out the first root (Plate XX XIX, 8). The root also bears a 
number of the root-hairs. With the exception of the ones at the tips 
of the roots, these root-hairs disintegrate as the plant further develops. 
At about the same time that the first root appears, the formation of the 
second leaf may be seen at the crown of the young plant (the outpushing 
embryo or cotyledon is considered the first leaf). This second leaf soon 
penetrates the epidermal cells of the first leaf, and comes out to grow 
and function as a true leaf (Plate XX XIX,9). After all the food material 
in the seed has been absorbed, the tip of the first leaf either disintegrates 
and is thus loosened from the seed, or the tip of the leaf is wrthdrawn 
from the seed (Plate XX XIX, 10). The successive stages of the growth 
of the plant are shown in Plate XX XIX, 4-10. 
