18 
BULLETIN 1450, U. S. DEPARTMENT OF AGRICULTURE 
NUMBER OF INTERNODES PER SHOOT 
A series of experiments was conducted for the purpose of de- 
termining whether the number of internodes of timothy shoots is 
relatively constant or whether it varies to any marked degree. 
In order to get data for the 
solution of this problem, shoots 
were selected on different plants 
and records were obtained 
from them in the following 
manner : Each shoot was ex- 
amined early enough so that 
an accurate count could be 
made of all leaves, includ- 
ing the coleophyll on seedlings 
and the prophyllum of lateral 
shoots on older plants. One of 
the growing leaves on each 
plant was marked with insol- 
uble ink and a record was made 
of its position. The shoot was 
observed at intervals, and a 
new leaf was occasionally 
marked. Since there is an in- 
ternode above the node from 
which each leaf grows, if a 
record is obtained of the num- 
ber of leaves which develop on 
a shoot, then the number of 
internodes can also be deter- 
mined. 
Each one of the shoots for 
which a record is presented in 
Table 9 produced a head on 
which florets bloomed and seeds 
formed during June and July. 
Six groups of shoots were 
studied. These groups are ar- 
ranged in two classes. In the 
first class of groups, A-l to 
A-3, inclusive, the shoots grew 
directly from seeds. In the 
second class of groups, B-l to 
B-3, each shoot developed from 
a bud in the axil of a leaf of 
an older shoot. 
The cultural conditions un- 
der which the plants of each 
group were grown are de- 
scribed below: 
Group A-l.— These shoots were grown from seeds sown in a broadcast plat 
on September 13, 1918. 
Group A-2. — Seeds were sown in a box of soil about March 1, 1916. The 
box was kept in a warm room and the soil was watered at intervals until 
Fig. 4. — Diagrammatic drawing of a timothy 
shoot hearing a head. The relative posi- 
tions of the parts composing the stem or 
axis are indicated, a to h, Proaxis ; btoc, 
haplocorm ; c to d, culm ; d to e, rachis 
(the axis of the inflorescence) 
