E72 BOTANICAL GAZETTE [MARCH 
ledons are sessile (fig. 16) and hairy near the base on both faces; 
the stipules are represented by two linear, very small lobes, which 
bear very long and sharply pointed hairs. The leaves succeeding 
the cotyledons show the typical shape of the species and the stipules 
consist of several linear, hairy lobes. In mature specimens, which 
are annual, the primary root becomes very strong and woody; the 
main stem is erect, with many horizontal or ascending lateral branches, 
and the rigid, scabrous leaves are sessile and horizontal. 
The roots.—The primary root shows secondary formations at an 
early stage, so that the primitive organization of the stele becomes 
obliterated. The epidermis, the cortex, and the endodermis become 
thrown off, and a cork of about four strata is developed from the 
pericambium; a large mass of leptome, hadrome, and thick-walled 
conjunctive tissue occupies the greater portion of the cross-section. In 
lateral roots of the first order epidermis is partly thrown off and there 
is no exodermis. The cortical parenchyma consists of four layers 
of large, thin-walled cells; the endodermis is also thin-walled and 
shows the Casparyan spots very plainly. Divisions have commenced 
to take place in the pericambium, and arches of cambium inside the 
leptome and outside the proto-hadrome have developed. The primi- 
tive structure is yet observable, there being five rays of hadrome 
alternating with five groups of leptome. 
The lateral roots of the second order are capillary and show no 
increase in thickness. The epidermis is hairy and covers directly 
the cortex of two layers of very large, thin-walled cells. The endo- 
dermis is thin-walled, and the pericambium, which is continuous, sur- 
rounds two groups of leptome and one diametric row of narrow 
vessels. 
The stem.—Numerous bicellular and rather thin-walled pointed 
hairs cover the stem from apex to base; the outline of the internodes 
is obtusely quadrangular, with two concave and two slightly convex 
faces. The cuticle is very distinctly wrinkled except over the hairs, 
where it is perfectly smooth. The epidermis is moderately thickened 
on the outer cell walls, and stomata are quite frequent. A few strata 
of collenchyma in a continuous zone separate the epidermis from 
the cortex, which consists of about four layers with narrow intercellular 
spaces. Chlorophyll was observed in the cortex, though in small 
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