UF BOT 2710: Practical Plant Taxonomy: Lab 3: Vegetative characters

This lab was designed to teach you some useful vegetative characters for plant identification and that are really important for the rest of the class. You can read more about vegetative characters on Chapter 4 of the text book. At the bottom of each picture you are going to have the scientific names of the plants that you saw in lab. It is a good exercise to get familiarized with the names and also with this system of assigning names to plants.
The lab had examples of:

I. Duration: we did not have examples of "duration" in class but you can think about seasonality and how is that related to plants, do all plants come back after the winter?

II. Roots function as an anchorage, absorption and storage organ for the plant. These are different examples of roots that you observed in the lab.

A. Taproots

Sida rhombifolia

Daucus carota

B. Fibrous roots

Megathyrsus maximus (left) & Eleusine indica (right)

In this specimen you were able to see two root types: fibrous and adventitious

Stenotaphrum secundatum

C.Adventitious roots

Try to enlarge this picture in your browser and check the roots of this small leafless orchid, do you notice that they are photosynthetic? (green)

Dendrophylax porrectus

Clusia sp.

Phyla nodiflora

D.Aerial roots

Tillandsia recurvata

Special example: Ipomoea batatas (this is an example of tuberous roots)

III. Stems: they can be aerial or subterranean and divided into nodes, the points at which leaves are borne, and internodes, the areas between the nodes.

A. Rhizomes

Stenotaphrum secundatum

B. Tubers

Solanum tuberosum

C. Corms

Colocasia esculenta, besides the corm, this species also shows rhizomes

D. Bulbs

Allium cepa

Important questions: Where are the carbohydrates stored in a corm? bulb?

E.What is the difference between thorns, spines and prickles? What is the function/s of these structures?

Thornes

Citrus trifoliata

Spines- note the green fleshy stem

Opuntia

Prickles

Rubus cuneifolius

V. Leaves: they function as photosynthetic organs, generally broad and/or flattened and borne at the nodes of a stem. In flowerng plants just above the point of attachment of the leaf base or petiole there is an axillary bud.

A. Leaf arrangement.

Alternate leaves

Prunus caroliniana

Opposite leaves

Viburnum odoratissimum

Whorled

Nerium oleander

Clerodendrum indicum

B. Parts and features of leaves

Identify parts of a leaf, leaf venation, leaf margins, apex and base of leaves: In this part of the lab you were asked to identify the following structures in different plant species, you need to be able to distinguish:

Parts:

1. pulvinus

2. petiole

3. blade

4. stipules

5. leaf axil

6. adaxial and abaxial surfaces

7. compound vs. simple leaf

8. pinnately vs. palmately compound leaf

9. A sessile leaf

We recommend you to use all these pictures to review all of the terms mentioned above

Cercis canadensis

Check the large stipules present in this plant

Dombeya x cayeuxi

This specimen has pinnately compound leaves

Carya glabra

Contrast the previous specimen with this one that has palmately compound leaves

Casimiroa edulis

This plant has unifoliolate leaves, this is an example of a compound leaf that has been reduced to a single leaflet, observe carefully the base of the leaf.

Citrus aurantiaca

This is an example of sessile leaves

Eucalyptus sp.

Types of leaf venation:

1. Parallel - most of the monocots have parallel leaves

2. pinnate

Carpinus caroliniana

3. Palmate

Liquidambar styraciflua

Leaf variation: the following section tries to show you the diversity of leaf forms. As an exercise try to describe them using the appropriate botanical terms, and make sure that you can identify if leaves are simple, compound, types of margins, shapes of the base and apex. Remember to look at both sides of the leaves (abaxial and adaxial), since some important identification features can be located on one side of the leaf only (hairs, domatia, pellucid dots, etc).

This is an example of lobed leaves, look at the shape, apex, base, venation