Branch Angle Climbers

Plants forming attachments via wide-angled branching also show widely differing patterns of change in Estr The species of Croton, representing a woody dicotyledon (Figure 2.6a), shows a similar trend as the majority of twiners and tendril-climbers (Table 2.1; Figure 2.3 and Figure 2.4). The young parts of climbing stems have high values of Estr and above the general range of nearly all twiners and most of the hook climbers and tendril climbers. The older parts show a marked drop in Estr with values

Bending properties of old stages

Secamonopsis madagascariensis Secamone ligustrifolia Secamone geayii Secamone cristata Secamone buxifolia Secamone bosserii Pervillaea philipsonii Maripa scandens Machaerium sp. Lonicera sempervirens Lonicera reticulata Lonicera periclymenum Lonicera alseuosmoides Gnetum cf. guianensis Gnetum bucholzianum Gnetum africanum Fallopia albertii Doliocarpus sp. Condylocarpon guianense Aristolochia macrophylla Aristolochia gigantea Aristolochia brasiliensis

Smilax aspera Passiflora glandulifera Clematis vitalba Clematis flammula var. maritima Bauhinia guianensis

Strychnos sp. Rosa canina Plectocomia himalayana Desmoncus polyacanthos Desmoncus orthacanthos Daemonorops jenkinsiana Calamus tetradactylus Calamus acanthospathus Bougainvillea glabra

Lycopodiella cernua Ischnosiphon centricifolius Croton pullei Croton nuntians

Lonicera xylosteum Lonicera myrtillus Clematis recta

Stem twiners

Tendril climbers

Hook climbers

Branch angle climbers

Leaning climbers

2000 4000 6000 8000 10000 12000 14000 16000 18000 Structural Young's modulus (MNm-2)

FIGURE 2.4 Mean structural Young's modulus and one standard deviation of old stages of development of climbing plants with different modes of attachment. Black bars = dicotyledons, stippled bars = gymnosperms, white bars = monocotyledons, striped bar = lycopod.

of less than 1000 MNm-2, approaching that of many tendril climbers and twiners and, interestingly, well below that of all of the other hook climbers.

Stems of Lycopodiella cernua interlock with the surrounding vegetation via lateral branches. The younger parts of the plant show relatively stiff mechanical properties of over 8000 MNm-2, in the range of woody rigid species like Bauhinia and Strychnos (Table 2.1; Figure 2.3 and Figure 2.4). The older stage at the base of the plant is more flexible but still retains high values of around 3000 MNm-2.

Finally, the monocotyledonous branch climber, Ischnosiphon centricifolius (Marantaceae) has highly characteristic "pencil-like" stems, which produce rosettes of leaves at nodes along the stem (Figure 2.6b and 2.6c). Both the leaves and the angle formed by the insertion of the next internode can anchor the plant stem onto surrounding host plants in the forest understory. Younger distal parts of the climbing

TABLE 2.1

Structural Young's Modulus, Attachment Type, Size, Diameter, and Taxonomic Group of 43 Tested Climbing Plants from 18 Different Vascular Plant Families, Arranged according to Attachment Type

Species

Leaning

Notes

Eta [MNm-2] Young Stages

Eta [MNm-2] Old Stages

Climbing to: Forest Canopy Forest Understory Herb to Shrub Level Herb Level

Diameter Of Widest Stem Tested [Mm]

No. of Samples (Young Stages)

No. of Samples (Old Stages)

Family

Group

Leaning

Clematis recta

**

b

4521 ± 980

5132 ± 1200

Herb to shrub

6

20

33

Ranunculaceae

Dicot

Lonicera myrtillus

**

f

3560 ± 939

2978 ± 560

Forest understory

10

3

7

Caprifoliaceae

Dicot

Lonicera xylosteum

*

f

7022 ± 2497

7790 ± 2222

Forest understory

18

4

5

Caprifoliaceae

Dicot

Angled Branch

Croton nuntians

*

d

8318 ±

2401

849 ± 211

Croton pullei

*

e

6741 ±

2206

490 ± 203

Ischnosiphon centricifolius

*

4956 ±

921

10427 ± 921

Lycopodiella cernua

*

e

8719 ±

1571

3031 ± 2054

Hook

Bougainvillea glabra

**

a

3640 ±

219

3460 ± 1113

Calamus acanthospathus

*

i

6110 ±

1560

1830 ± 670

Calamus tetradactylus

**

i

7070 ±

1560

2300 ± 500

Daemonorops jenkinsiana

**

6630 ±

1330

-

Desmoncus orthacanthos

*

i

4000 ±

1070

8906 ± 2240

Desmoncus polyacanthos

*

5074 ±

1782

8091 ± 2546

Plectocomia himalayana

*

3250 ±

1030

4120 ± 780

Rosa canina

*

h

1848 ±

787

3155 ± 954

Strychnos sp.

*

a

12920 ±

3790

1750 ± 40

Forest canopy Forest canopy Forest understory

Forest canopy Forest canopy Forest canopy

Forest canopy Herb to shrub Forest canopy

Forest canopy Forest canopy Forest understory

Forest canopy Forest canopy Forest canopy

Forest canopy Herb to shrub Forest canopy

49 102 15 4

14 38 5 10

41 3

13 8

17 16 3 12

Euphorbiaceae Euphorbiaceae Marantaceae Lycopodiaceae

Dicot Dicot Monocot Lycopsid

20

Nyctaginaceae

Dicot

n 0

2

Arecaceae

Monocot

40

Arecaceae

Monocot

era -<

-

Arecaceae

Monocot

a

9

Arecaceae

Monocot

Q.

11

Arecaceae

Monocot

CC

3

Arecaceae

Monocot

0 3

23

Rosaceae

Dicot

(D O

2

Loganiaceae

Dicot

»

Tendril

Balthinia guianensis

*

a.g

Clematis fiammula var.

*

b

maritima

Clematis vitalba

*

b

Passiflora glandlllifera

*

a

SmilcLX aspera

*

Stem Twiner

Aristolochia brasiliensis

**

Aristolochia gigantea

**

Aristolochia macrophylla

**

b

Condylocarpon guianense

*

c

Doliocarpus sp.

*

a

Fallopia albertii

**

a

Gnetlim africamtm

*

Gnetum bucholzianum

*

Gnetum cf. guianensis

*

Lonicera alseuosmoides

**

f

Lonicera periclymenum

*

f

Lonicera reticulata

**

f

Lonicera sempervirens

**

f

Machaerium sp.

*

a

Maripa scandens

*

a

Pervillaea philipsonii

*

Secamone bosserii

*

Secamone buxifolia

*

Secamone cristata

*

Secamone geayii

*

8-180 ± 2820

350

±

100

Forest canopy

1619 ± 492

470 ±

113

Herb to shrub

3074 ± 1083

772

±

261

Forest canopy

4540 ± 620

630

±

130

Forest canopy

3178 ± 1057

4937

±

529

Herb to shrub

1955 ± 411

104

±

72

Forest canopy

3343 ± 1405

294

±

89

Forest canopy

2465 ± 479

497

±

385

Forest understory

2720 ± 900

310

±

50

Forest canopy

6870 ± 980

290

±

30

Forest canopy

2740 ± 290

730

±

150

Forest canopy

1036 ± 176

560

±

64

Forest canopy

683 ± 180

293 ±

90

Forest canopy

3037 ± 126

961

±

222

Forest canopy

4561 ± 1330

1170

±

342

Forest understory

4050 ± 894

1912

±

444

Forest understory

4028 ± 1589

1876

±

528

Forest understory

4666 ± 1516

3262

±

796

Forest understory

5750 ± 2110

1200

±

150

Forest canopy

4111± 510

390

±

30

Forest canopy

1851± 232

266

±

79

Forest canopy

4573 ± 818

1793 ±

305

Herb to shrub

3145 ± 693

850

±

85

Forest canopy

4057 ± 851

1158

±

357

Forest to shrub

4909 ± 647

1415

±

396

Herb to shrub

18

3

3

Fabaceae

Dicot

10

21

10

Ranunculaceae

Dicot

18

18

17

Ranunculaceae

Dicot

21

3

3

Passifloraceae

Dicot

6

7

7

Smilacaceae

Monocot

35

6

8

Aristolochiaceae

Dicot

23

6

5

Aristolochiaceae

Dicot

28

40

45

Aristolochiaceae

Dicot

38

36

11

Apocynaceae

Dicot

33

3

3

Dilleniaceae

Dicot

13

10

3

Polygonaceae

Dicot

24

2

4

Gnetaceae

Gymnosperm

17

11

7

Gnetaceae

Gymnosperm

17

2

3

Gnetaceae

Gymnosperm

7

10

2

Caprifoliaceae

Dicot

24

3

6

Caprifoliaceae

Dicot

9

8

5

Caprifoliaceae

Dicot

12

8

3

Caprifoliaceae

Dicot

29

3

3

Fabaceae

Dicot

32

5

3

Convolvulaceae

Dicot

IS

12

11

Apocynaceae

Dicot

12

12

6

Apocynaceae

Dicot

17

12

6

Apocynaceae

Dicot

11

9

2

Apocynaceae

Dicot

11

8

6

Apocynaceae

(continued)

TABLE 2.1 (CONTINUED)

Structural Young's Modulus, Attachment Type, Size, Diameter, and Taxonomic Group of 43 Tested Climbing Plants from 18 Different Vascular Plant Families, Arranged according to Attachment Type

Species

Notes

Fstr [MNm-2] Young Stages fstr [MNm-2] Old Stages

Climbing to: Forest Canopy Forest Understory Herb to Shrub Level Herb Level

Diameter Of Widest Stem Tested [Mm]

No. of Samples (Young Stages)

No. of Samples (Old Stages)

Family

Group

Stem Twiner (continued)

Secamone ligustrifolia Secamonopsis madagascariensis

1976 ± 544 767 ± 105 Forest canopy 1734 ± 413 570 ± 192 Forest canopy

29 23

12 12

Apocynaceae Apocynaceae

Dicot Dicot

Note: Values of Es1r are based on means and 1 standard deviation.

* Plant measured in natural habitat ** Plant measured in botanical gardens or greenhouses. a See ref. [8] b See ref. [27] c See ref. [7] d See ref. [21] e See ref. [15] f See ref. [25]

g Old stems of Bauhinia guianensis are ribbon-shaped; the maximum diameter given here corresponds to the diameter of a circular surface equal in area to the ribbon-shaped stem in cross section.

h Measurements of Rosa canina are confined to leaning or climbing stems up to 1 year old.

i Data for these climbing palms include measurements based on old stages in which the outer leaf sheath has been lost via natural aging. The other species are all based on older portions of climbing stems in which the leaf sheath is still attached but usually, at least, partially senescent.

CTQ a

FIGURE 2.5 (a) Young phase of growth of the understory climbing palm Desmoncus polya-canthos (French Guiana). When the plant becomes mechanically unstable, it produces leaves equipped with distal hooks and grapnel-bearing cirri (left). (b) Young phase of growth of Calamus acanthospathus (Yunnan Province, China). When the plant becomes unstable, long modified inflorescences bearing recurved hooks (flagellae) are produced, and the plant can reach the canopy, producing stems over 70 m in length. (c) The calamoid rattan palm Plecto-comia himalayana (Yunnan Province, China), old stage of development in which the young part of the plant is firmly attached in the canopy and the older part of the axis is spanning a wide space between supports. The leaves and leaf sheaths of this part of the stem are senescing and lose their attachment with the original supports. (d) Apical parts of P. himalayana emerge from the forest canopy (Yunnan Province, China) and bear many cirrus-bearing leaves and many potential attachment points with the surrounding canopy vegetation. (e) The small-bodied Smilax aspera (southern France) uses both apendicular tendrils and recurved hooks for attaching to host plants. Tendrils firmly connect the plant to the host. (f) Apex of the attachment organ (cirrus) of Desmoncuspolyacanthos (French Guiana) produce laterally deployed grapnellike modified leaflets (acanthophylls) and abaxially placed recurved spines.

FIGURE 2.6 (a) The branch-angle climber Croton nuntians (French Guiana) shows a well-attached apex and flexible older stems descending to ground level. (b) The climbing monocotyledon Ischnosiphon centricifolius (French Guiana). Its narrow pencil-like stems ascend into the understory. (c) The angles formed between successive nodes and internodes in stems of Ischnosiphon centricifolius provide effective points of attachment. (d) Stiff distal branches and sensitive hooks of Strychnos sp. (French Guiana). (e) Unattached hook of Strychnos sp. When hooks locate a host branch, they can develop a more secure attachment by tendril-like growth and woody development (French Guiana). (f) Appendicular woody tendrils produced from Bauhinia guianensis. Such structures can form firm attachments to narrow diameter host branches (French Guiana).

FIGURE 2.6 (a) The branch-angle climber Croton nuntians (French Guiana) shows a well-attached apex and flexible older stems descending to ground level. (b) The climbing monocotyledon Ischnosiphon centricifolius (French Guiana). Its narrow pencil-like stems ascend into the understory. (c) The angles formed between successive nodes and internodes in stems of Ischnosiphon centricifolius provide effective points of attachment. (d) Stiff distal branches and sensitive hooks of Strychnos sp. (French Guiana). (e) Unattached hook of Strychnos sp. When hooks locate a host branch, they can develop a more secure attachment by tendril-like growth and woody development (French Guiana). (f) Appendicular woody tendrils produced from Bauhinia guianensis. Such structures can form firm attachments to narrow diameter host branches (French Guiana).

stem show relatively high values of Estr of around 5000 MNm-2, which is in the upper range of values for twiners and hook climbers. Interestingly older, more basal parts of the plant show very high values of Estr of over 10,000 MNm-2 (Table 2.1; Figure 2.3 and Figure 2.4).

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