Root Modifications
Most dicots form a tap root system:

radical persists: becomes main root with lateral branches.
Most monocots form a fibrous root system:

radical dies: roots arise from stem tissue (adventitious).
Root modifications to know: adventitious roots, storage tap
root, storage tuberous roots, storage fleshy roots, and
aerial roots.
Tap roots (dicots) and fibrous roots which are formed adventitiously (monocots).
Modifications - Root
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Adventitious root arising from the
vascular cambium of the stem
Adventitious roots of English ivy, climbing hydrangea, and philodendron (dicots).
Modifications - Root
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Adventitious roots on a chrysanthemum cutting (dicot) and on lily bulbs (monocot).
Modifications - Root
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Storage fleshy roots of daylily (Hemerocallis) – a monocot and still is a fibrous root system.
Modifications - Root
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Aerial root on an epiphytic orchid (Phalaenopsis) – a monocot with a fibrous root system.
Modifications - Root
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Storage tap roots of carrot, horseradish, and beet (dicots).
Modifications - Root
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dahlia
Genus /
species
Class
Plant Type
Organ
modification
True yam
Sweet potato
Dioscorea spp.
Ipomoea batatas cvs.
monocot
vine
tuberous roots
dicot
vine
tuberous roots
yam
Storage tuberous roots of dahlia (dicot), yam, and of two sweet potato cultivars.
Modifications - Root
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Ectomycorrhizae formed by five species of fungi (over 2000 spp. can colonize conifers in the
Pinaceae): enhances N,P,K, water uptake, protects root tips from pathogens & desiccation.
Modifications - Root
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alder
clover
Root nodules of alder (which contain Frankia) and clover (which contain Rhizobium). The
bacteria inside can fix atmospheric nitrogen gas and convert it into a form the plant can use
as a source of nitrogen (do NOT confuse with ETM – no fungus can do this!).
Modifications - Root
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