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External Structure of the Vascular Plant
There are two representative plants to look at; a bean plant, Phaseolus vulgaris and a "fast plant" or rapid cycling Brassica rapa (RCB). You will see the RCB mentioned several times in the lab section of the syllabus as we will use it for many purposes. So this is kind of an introduction to RCB's and plants in general. Take some time to identify the following parts and label them on the diagrams:
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primary or tap root |
(look at the roots on the plants we have washed out) |
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branch or lateral root |
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cotyledons |
node |
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simple leaves |
internode |
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compound leaves |
axil |
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leaflet |
axillary bud |
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Blade or lamina |
stipule |
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petiole |
flower and fruit (if present) |
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rachis |
hypocotyl |
There are many similarities between the two plants but consider
the following questions.
Do the stems of both plants look like they could go on growing? (Technically are they indeterminate?)
Do both plants have stipules?
What is the difference between a stem and a petiole - how could you tell them apart?
Do these plants have opposite or alternate leaves?
Where is the inflorescence in these plants?