28 
PRINCIPIA 
THE PRINCIPAL 
OUTLINES OF A PLANT, 
Al plant principally consists of root, trunk , leaves, props, 
fructification, and irforescence ; and also the habit. 
I. The ROOT consists of two parts, (viz.) the caudex and 
the radicula, distinguished according to shape, direction, 
duration, &c. 
Caudex (a stump) is the body or knob of the root, from 
which the trunk and branches ascend, and the fibrous roots 
descend; and in different plants is either solid, bulbous, 
(placed under a bulb, as in tulips , Sec. or above the bulb, as 
in orchis, See.) or tuberous. Solid, as in trees, shrubs, and 
many of the herbs. Bulbous will be explained under hybtr - 
nacle. Tuberous knobs* are also solid and hard, containing 
one or more embryos or eyes ; and are either only one knob, 
as turnep, carrot. Sec. containing only one eye at the top; or 
consist of many knobs connected together by slender fibres, as 
in potatoes, Jerusalem artichokes, &,c. each containing many 
eyes dispersed over the surface ; and are either pitted, when 
the eyes lie inward, as in potatoes, &c.; or tuberculed, con-* 
taining the eyes outward, as in Jerusalem artichokes, &c. In 
tuberous knobs, the fibres or stringy parts issue from different 
*. Those tuberous knobs with only one eye, differ as to duration, but are in 
general biennial; those with many eyes are perennial; both seem to be produced 
by the nutriment of the stem, and not by the fibrous roots, for the stem is first 
formed and becomes strong, and as it grows to maturity, the tuberous knobs in¬ 
crease; or as it is said in Phytologia , not until after the leaves are expanded in the 
air to oxygenate the vegetable blood* It is also said that pinching off the flowers 
of the potatoes, will increase the size and quantity of the roots, by adding to the 
roots the nourishment required for the flowers and seeds .—Tuberous roots are in¬ 
creased in number by a seminal chord which proceeds under ground from the old 
root, after the leaves are expanded ; in the same manner as the wires of straw* 
berries, which maybe called seminal chords above ground, and the design seems 
evidently to place the offspring at a convenient distance trom the parent plant, that 
they may not incommode each other, Phytologia. 
