Week 14 Laboratory


<Lab Schedule>

I. Demonstrations. This lab will cover all the monocots. Look at these in as much detail as you want, but be sure to identify and understand the characters indicated on the sheet next to each demonstration. Refer to your lecture handouts, Plant Systematics [T], and the Zomlefer [Z] resource for more details.

   1. Alismatales: Anthurium, Aglaonema, Spathiphyllum (Araceae) (pp. 160-163 [T], 301-303 [Z])

A primitive monocot group; find the spathe and spadix in the plants shown here.
The inflorescence of Araceae are usually composed of unisexual flowers. Examine the spadices and determine where are located the female, male, and (possibly) neuter floral regions.


   2. Alismatales: Pistia (Araceae - water lettuce) (pp. 160-163 [T], 301-303 [Z])

Once considered the "missing link" between terrestrial Araceae and the aquatic Lemnaceae, Pistia is now clearly just another aquatic Araceae.
Tear a small piece of one leaf; do you see the specialized tissue that permit water flotation? This tissue is composed of aerenchyma.
Look carefully in between the smallest leaves, what do you see in there (be specific)? . Once you have figured that out, look at the illustration on the right to verify your answer.


   3. Alismatales: Spirodela, Lemna and Wolffia (Lemnaceae - duckweeds; now placed in Araceae) (pp. 160-163 [T], 301-303 [Z])

These are the smallest Angiosperms. None are in flower, but note the vegetative features under the microscope. The entire plant consists of a tiny leaf and little rootlets. The plants reproduce mostly vegetatively and flowers are rare.


   4. Lilioids: Paphiopedellum and Oncidium (Orchidaceae - orchids) (pp. 171-177 [T], 293-297 [Z])

Paphiopedellum belongs to the subfamily Cypripedioideae (lady slippers).
- calyx consists of 3 sepals (connation is occurring!)
- one of the 3 petals is modified to form a pouch like labellum
- this subfamily has 2 stamens and does not have true pollinia
- note the inferior ovary; how many carpels would you expect to be present?

Oncidium belongs to the more derived subfamily Orchidoideae
- find the perianth parts; are they different than in the lady slippers?
- orchids are considered up-side-down flowers or resupinate, as the labellum is morphologically the topmost petal. Do you see any evidence of this twisting?
- this subfamily has only one stamen with generally one or two pollinia.
- the fertile stamen and sterile stamens are fused to the style and stigmas to form a column; can you find this structure? A beak or rostellum is modified from the one sterile stigma; locate this structure.


   5. Commelinids: Avena (Poaceae or Gramineae - oats) (pp. 213-219 [T], 350-356 [Z])

Grasses, and their relatives the sedges, are the most advanced commelinoids and also the most reduced florally.

Use your lecture handout (with lecture outlines) illustrating the makeup of grass florets (the flower) and spikelets (the inflorescence) to understand and recognize the basic parts of the grass flower and inflorescence [a copy available to your right].

In the dissected oats spikelet, find the two bracts called glumes enclosing each set of florets. How many florets in each spikelet? Find the two bracts called lemma and palea that enclose each individual floret. Locate the stamens and ovary. Are they present in each floret? If you can, also locate the lodicules.


II. Additional representatives of these and other families are placed around the room. As time permits, examine these plants and especially note the floral structures. You will not be required to know these plants; they are simply provided to illustrate additional members of these families. AL = Alismatales, L = Lilioid, C = Commelinid

1. Araceae [AL]: Anthurium, Alocasia, Aglaonema, Spathiphyllum, Colocasia (taro)
2. Aponogetonaceae [AL]: Aponogeton madagascariensis (water hawthorn, lace plant)
3. Potamogetonaceae [AL]: Potamogeton (pond weed)
4. Liliaceae (in broad sense) [L]: Amaryllis [Alliaceae], Allium ([Alliaceae - onion), Asparagus [Asparagaceae] Aloe [Xanthorrhoeaceae], Agave [Xanthorrhoeaceae], Lilium (lily)
5. Iridaceae [L]: Iris (iris), Gladiolus, Freesia
6. Dioscoreaceae [L]: Dioscorea (yam)
7. Orchidaceae
[L]: Dendrobium, Dortitis, Epidendrum, Phalenopsis.
8. Arecaceae
[C]: (Palmae): Phoenix (date palm).
9. Zingiberaceae
[C]: Hedychium, Zingiber (ginger).
10. Costaceae
[C]: Costus.
11. Marantaceae
[C]: Maranta (prayer plant).
12. Cannaceae
[C]: Canna.
13. Bromeliaceae
[C]: Ananas (pineapple), Billbergia, Brocchinia, Cryptanthus, Navia, Neoregellia, Vriesea.
14. Commelinaceae
[C]: Dichorisandra (blue ginger), Rhoeo, Setcresea, Zebrina.
15. Pontederiaceae
[C]: Eichhornia (water hyacinth).
16. Cyperaceae
[C]: Cyperus (dwarf papyrus), Scirpus (bulrush).
17. Poaceae
[C]: Lithachne (bamboo), Pharus (bamboo), Oryza (rice), Zea (corn), Hordeum (barley), Agrostis, Andropogon, Digitaria, Panicum, Pennisetum, Rhynchelytrum.


III. 14 genera of Wisconsin plants to be able to identify on site. AL = Alismatales, L = Lilioid, C = Commelinid

1. Sagittaria (Alismataceae - arrowhead) AL
2. Arisaema (Araceae - jack-in-the pulpit) AL
3. Erythronium (Liliaceae - trout lily, dog-toothed violet) L
4. Trillium (Melianthaceae - trillium) L
5. Polygonatum (Asparagaceae - Solomon's seal) L
6. Maianthemum (Asparagaceae - wild lily-of-the-valley) L
7. Smilax (Smilacaceae - catbriar, greenbriar) L
8. Iris (Iridaceae - iris, blue flag) L
9. Cypripedium (Orchidaceae - lady slipper) L
10. Tradescantia (Commelinaceae - spiderwort) C
11. Typha (Typhaceae - cattail) C
12. Carex (Cyperaceae - sedge) C
13. Andropogon (Poaceae - bluestem, turkeyfoot) C
14. Bouteloua (Poaceae - grama grass) C

IV. Check your plant collections for any specimens that belong to these groups of monocots and key them out using Gleason and Cronquist if you have not done so already.