the Embryo and Seedling in the Gramineae. 183 
understood. For as the seed of Zizania will only germinate under water, 
the scutellurn does not require special adaptations for rapid water con¬ 
duction. 
Leersia oryzoides, Sw. The three seedlings which we have examined 
are all about the same age. The first and second leaves are free from the 
coleoptile, and the second is unrolling as it leaves the shelter of the first leaf. 
In this species the first leaf is reduced to a membranous sheath, but the 
second is a fully-formed foliage leaf. 
The species is aquatic, and the seedling resembles that of Zizania 
in general habit. The chief points of difference, excluding the smaller size, 
are the reduction of the first leaf to a sheathing organ, and the formation of 
cauline roots from the insertion zone as well as at the first node. It will be 
seen that the anatomical differences between Leersia and Zizania are 
correlated to these external features. 
The coleoptile is open and unstififened ; the epiblast leaf-like, and the 
mesocotyl slender. The primary root is developed much earlier than any 
cauline root, and is freely branched. 
The bundle of the scutellurn is slender. It enters the axis at the 
apparent insertion, and turns sharply upwards without joining the stele, as 
in all seedlings of this type. 
Just above the first node six lignified plumular traces form a single 
circle in the axis ; outside these are the traces from the coleoptile. The 
three traces from the second leaf are much larger than those from the first, 
probably because the second is a foliage leaf while the first acts only 
as a sheath. A xylem girdle is formed here, as in Zizania , in which the 
identity of all the plumular traces is lost. A gap appears in the girdle just 
before the coleoptile traces have reached the stele. They run in from either 
side along a tangent touching the stele at this gap. 
As the traces approach the stele, the xylem of each divides ; one branch 
entering the stele, the other remaining outside it. The inward branches 
unite to form a xylem group within the stele, which does not long retain its 
identity. The outward branches meet outside. The phloem of each 
coleoptile trace is already double; one group accompanies the inward, 
the other the outward branch. Thus a double phloem group is formed 
within and without the stele, but both become single almost immediately. 
The complete bundle outside the stele is of course the inverted scutellurn 
trace. As in Zizania it is not directly connected with the stele by xylem 
elements. 
The stele of the mesocotyl just below the first node is slender but very 
well differentiated. The cells of the endodermis are thickened, especially 
on the inner and radial walls. The pericycle consists of a single row 
of thickened elements, some of them lignified. The later xylem plates of 
