Sampling

We present values of structural Young's modulus Estr for a wide taxonomic and morphological range of climbers; the results are presented as means and standard deviations for young and old developmental stages of climbing plants (Figure 2.3 and Figure 2.4; Table 2.1). Despite problems in assigning specific ages for young and old plant segments, young axes of the plant are generally positioned toward the apex and, often in climbing plants, represent "searchers" for reaching new hosts (Figures 2.1a and 2.1b). In general, older stages of development represent more basal and generally, but not always, more flexible parts of the climbing plant (Figures 2.1c and 2.1e) [10,19]. The object is to compare how mechanical properties vary with type of attachment among different plant groups. Attachment modes were summarized as:

1. Twining or winding of the main leading axis and/or principal branches.

2. Attachment to the host plant via sensitive tendrils or tendril-like organs. There are a range of such types of organs derived from stem, leaf, or fertile axis. For simplicity, we have grouped these together. From a mechanical perspective and in terms of the growth form of the whole plant, we suspect that these types of attachment act similarly.

3. Attachment to host plants via hooks.

4. Attachment to host plants via wide-angled branches acting as anchors.

5. Leaning against the surrounding vegetation.

The analysis includes 43 species from 18 vascular plant families, including 1 lycopsid, 3 gymnosperms, 8 monocotyledons, and 31 dicotyledons (Table 2.1).

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