September, 1911 
thus to retain the under side of the stem in contact with an 
object to which the roots can afhx themselves. Another 
familiar example is the Tacoma, a plant classed with the 
Begonias, remarkable from the fact that not only does it 
produce quantities of climbing roots, but it also has a very 
pronounced twining stem. ‘Thus when the situation is not 
favorable for one method of growth, the resourceful plant 
is always able to adopt the other mode of affixing itself. 
It is clear that the thorns in many plants are useful as a 
protective measure, but in some instances it is found that 
these processes perform another office. Notably in the case 
of the Bramble (Rubus) and in some of the clambering 
Roses the prickles have been turned to account for the pur- 
pose of helping the plant to rise in the world. If these 
processes are examined it will be observed that the spines 
are of a curious hooked formation, such as would make it 
an easy matter for the shoot to become attached to any 
object. On occasion it is seen that the Bramble calls roots 
into action to help it to spread about. These are not 
adhesive, like the roots of the Ivy, and are only brought 
into service when a rooting medium is obtainable. Often 
enough a small quantity of vegetable mold will accumulate 
in the fork of a branch or between two rocks, and it is then 
that rootlets appear from the Bramble stem, and seize hold 
of the security offered. 
, Of the special processes which have been formed to meet 
the climbing needs of the plant the most strange are cer- 
tainly the tendrils. These organs, which are really meta- 
morphosed shoots, or altered parts of the leaf, at times 
seem as if they were endowed with something which is 
strangely like an intelligence. Some experiments conducted 
with the tendrils of a Pea plant showed that the organ grew 
out to a definite object with the greatest assurance. How 
the process could tell that the support was within reach, it is 
not at all easy to say. Ina general way the tendril, right 
trom its first appearance upon the scene, maintains an un- 
ceasing search for a support. This consists in a curious 
swaying movement just as if the plant knew that what it 
wanted to find called for a good deal of seeking before 
meeting with success. 
One of the most striking plants to observe, which climbs 
by means of tendrils, is the Passion Flower (Passiflora). 
These subjects occur widely in America, and represent in all 
a large range of forms, most of them producing very splen- 
did flowers, a fact which has caused them to be introduced 
as garden specimens all over the world. In their manner 
of attachment the Passifloras are very remarkable plants to 
watch. The tendrils which most of the species produce 
are very long and exceedingly sensitive. When the organ 
is in the highest state of its activity even the slight rubbing 
AMERICAN HOMES AND GARDENS 
337 
of its under side with the finger will in a few seconds cause 
the tendril to incline inwards. If a support, such as a cane, 
is placed within reach of the process, a very short time will 
elapse before the object is encircled. As a rule the tendril 
will not be content with merely looping itself once around 
the support, but in order to make quite sure that there can 
be no slipping away, doubles or trebles the circles. Now 
comes about a very curious change in the behavior of the 
organ. If the tendril is closely watched it will be seen that 
a small crank-like process is formed; this, it may be noted, 
continues to make complete revolutions, swinging down- 
wards and upwards with the greatest regularity. As this 
takes place the tendril is naturally coiled on either side of 
the crank portion, in one direction on one side and in an 
opposite direction on the other. Finally the coiling process 
slows down and at last ceases, and then the crank-like part 
appears as a straight section placed between two spiral por- 
tions. At times it will be noted that the tendrils develop 
several series of alternating spirals, and thus there may be 
more than one straight section to be observed. The pur- 
pose which the spiral conformation of the tendril serves is 
clear. Ina general way we may be sure that it will tend to 
strengthen the organ, while certainly it allows a give in 
rough weather, and in this way prevents the plant from 
being torn away from its moorings. 
The tendrils of the Virginia Creeper offer an advanced 
form of the particular process. At the end of these organs 
are small sucker-like attachments which are able to adhere 
to slightly roughened surfaces. By a marvelous provision 
these tendrils are endowed with a tendency to negative helio- 
tropism, which causes them always to grow to the dark 
crevices, where, of course, they are much more likely to 
obtain a hold than would be the case out in the open. Per- 
haps even more remarkable are the little discs which are 
produced so abundantly by the Ampelopsis. The under side 
of these, if examined under the microscope, is seen to be 
thickly covered with very small hairs. Thus the plant is 
well able to climb even up a perpendicular wall, for the 
small cilia enter the composition of the brickwork and 
secure a very firm hold. ‘The grip thus obtained is very 
secure—so much so that the discs continue to adhere even 
after the plant is dead. As much as a pound in weight has 
been suspended from one disc without causing a cleavage. 
As in the case of the Ivy, it is seen that the shoots of the 
Ampelopsis tend to grow away from the light, and in this 
way bring the suckers into contact with the support. In- 
deed, the Ampelopsis must be regarded as one of the most 
interesting climbers in the world, albeit it is such a common 
garden subject that few people have perhaps ever given a 
thought to its many and diversified wonders. 
