OUTLINE OF STRUCTURAL BOTANY 11 
ascending at length, neither quite erect nor prostrate like its proxi- 
mate part; or like 
the strawberry (Fig. 
13), which sends 
out long slender, al- 
most horizontal 
stems, known as run- 
ners, each of which 
at length puts forth 
a cluster of leaves 
and a fasciculus of 
roots which find their 
way beneath the soil and then push out another or several run- 
ners from this new station. Runners less slender, such as those 
from the common antennaria, are 
called stolons (Fig. 14). A somewhat 
different form of prostrate stem is that 
of the creeping loosestrife (Lysim- 
achia), which lies flat upon the ground 
and throws out its fascicles of rootlets 
at the leaf-nodes (Fig. 15). 
Some of the stems of many shrubs 
and even of some trees droop, touching 
the soil at length and, taking root, give 
rise to new plants in this manner. The 
drooping stems of the black raspberry are examples of this form of 
stem among shrubs, those of the banyan among trees. 
But these weak stems 
do not in all cases run 
along the ground nor 
droop to take root like 
those just mentioned. 
Some of these weak 
stems are held in more 
or less upright positions by means of tendrils, which may proceed 
directly from the stem as modified branches, as in case of the 
grape vine, or which are modified leaf stalks, as we find them in 
case of the clematis, the pea, etc., or the stem may be held by 
prickers, as in case of galiums. Still other weak stems wind about 
more erect plants or other bodies, of which the hop, the bindweed, 
the convolulus and many trailing vines are examples (Fig. 16). 
