1. CAM102A Botany Week 4: Stems
Concept 4: Stem modifications

2. Stem modifications
Predominantly based on reproduction, ie vegetative or asexual
Include:
Stolons
Rhizomes
Tubers
Bulbs
Corms
Cladodes
Thorns
late 17th century: from earlier botanic (from French botanique, based on Greek botanikos, from botanē 'plant')

3. Stem modifications Stolon lateral stems that grow across the ground
new roots and shoots can grow from nodes
eg Viola odorata
late 17th century: from earlier botanic (from French botanique, based on Greek botanikos, from botanē 'plant')
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4. Stem modifications Rhizome underground stems
can be thick and fleshy (eg ginger Zingiber officinale) or not (eg nettle Urtica dioca)
late 17th century: from earlier botanic (from French botanique, based on Greek botanikos, from botanē 'plant')
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5. Stem modifications Tuber underground stem for storage of starch
grow from the end of a stolon or rhizome
the ‘eyes’ are the axils and contain axillary buds
late 17th century: from earlier botanic (from French botanique, based on Greek botanikos, from botanē 'plant')
eg potato
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6. Stem modifications Bulb (A)
small stem surrounded by modified, fleshy leaves
eg Allium cepa
Corm (B) fleshy stem surrounded by thin scales (residual leaves)
eg daffodil
late 17th century: from earlier botanic (from French botanique, based on Greek botanikos, from botanē 'plant')

7. Stem modifications Cladode leaf like stem that can photosynthesise
eg prickly pear, asparagus, she oak and Ephedra sinica
late 17th century: from earlier botanic (from French botanique, based on Greek botanikos, from botanē 'plant')
prickly pear
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8. Stem modifications Thorn modifies stem for protection
not all thornlike objects are modified stems
ie spines are modified leaves eg prickly pear
prickles are modified hairs ie part of the epidermis eg rosaceae family
8. Tendrils
modified for climbing eg Vitis vinifera (grape)
late 17th century: from earlier botanic (from French botanique, based on Greek botanikos, from botanē 'plant')

9. References
Bidlack, J., & Jansky, S. (2011). Stern’s Introductory Plant Biology (12th edition) USA: Mc Graw Hill. Tan, E. (2001). Botany of the Flowering Plants. (2nd edition). Melbourne: NMIT. Cover image retrieved from: