=Scramblers.=--Some plants rise to light and air _by resting their long and weak stems on the tops of bushes and quick-growing herbs_. Their stems may be elevated in part by the growing twigs of the plants on which they recline. Such plants are scramblers. Usually they are provided with prickles or bristles. In most weedy swamp thickets, scrambling plants may be found. Briers, some roses, bed-straw or galium, bittersweet (_Solanum Dulcamara_, not the _Celastrus_), the tear-thumb polygonums, and other plants are familiar examples of scramblers. =Root Climbers.=--Some plants climb by means of _true roots_. These roots seek the dark places and therefore enter the chinks in walls and bark. The trumpet creeper is a familiar example (Fig. 36). The true or English ivy, which is often grown to cover buildings, is another instance. Still another is the poison ivy. Roots are distinguished from stem tendrils by their _irregular or indefinite position_ as well as by their mode of growth. [Illustration: FIG. 169.--TENDRIL, to show where the coil is changed.] =Tendril climbers.=--A slender coiling part that serves to hold a climbing plant to a support is known as a =tendril=. The free end swings or curves until it strikes some object, when it attaches itself and then coils and _draws the plant close to the support_. The spring of the coil also allows the plant _to move in the wind_, thereby enabling the plant to maintain its hold. Slowly pull a well-matured tendril from its support, and note how strongly it holds on. Watch the tendrils in a wind-storm. Usually the tendril attaches to the support by _coiling about it_, but the Virginia creeper and Boston ivy (Fig. 170) attach to walls by means of _disks_ on the ends of the tendrils. [Illustration: FIG. 170.--TENDRIL OF BOSTON IVY.] Since both ends of the tendril are fixed, when it finds a support, the coiling would tend to twist it in two. It will be found, however, that the tendril _coils in different directions_ in different parts of its length. In Fig. 169, showing an old and stretched-out tendril, the change of direction in the coil occurred at _a_. In long tendrils of cucumbers and melons there may be several changes of direction. Tendrils may represent either _branches_ or _leaves_. In the Virginia creeper and grape they are branches; they stand opposite the leaves in the position of fruit clusters, and sometimes one branch of a fruit cluster is a tendril. These tendrils are therefore homologous with fruit-clusters, and fruit-clusters are branches. In some plants tendrils are _leaflets_ (Chap. XI). Examples are the sweet pea and common garden pea. In Fig. 171, observe the leaf with its two great stipules, petiole, six normal leaflets, and two or three pairs of leaflet tendrils and a terminal leaflet tendril. The cobea, a common garden climber, has a similar arrangement. In some cases tendrils are _stipules_, as probably in the green briers (smilax).