Week 9 Laboratory

Rosids (part II)

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<Lab Schedule> <Next Lab>

I. Detailed floral dissection on fresh flowers. Include this section in your laboratory notebook with illustrations and labeled parts. Refer to Plant Systematics [T], Zomlefer [Z], and Gleason & Cronquist for descriptions of the species and families as needed.

 

A. Abutilon sp. (Malvaceae - abutilon, flowering maple) (pp. 280-286 [T], 90-94 [Z])

The Malvaceae is a member of the very distinctive order Malvales. The order is defined by a number of features. Note these features in the plants or flowers: stellate hairs [use your scope!], palmately veined simple or compound leaves, valvate sepals and staminal tube.

The gynoecium in the family is made up of variously numbered fused carpels. How many carpels are there [first take a look at the styles]? What kind of fruit is produced [if none present on the plants, look it up in your book].

Give a floral formula for Abutilon.

B. Lobularia maritima (Brassicaceae or Cruciferae - sweet alyssum) (pp. 278-281 [T], 125-130 [Z])

Brassicaceae represents an offshoot of the larger tropical family Capparaceae - now usually combined together as Brassicaceae. It is distinctive, however, in the number and position of stamens. What is unusual about these stamens?

The bicarpellate ovary shows what kind of placentation? Look for fruits (capsules) on the plants. Do you see the translucent membrane dividing the two carpels? What is this structure called? Is this special capsule called a silique or silicle?

Give a floral formula for Lobularia.

 

II. Demonstration floral dissections. 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 floral dissection. Be sure to understand how the four subfamilies of the Rosaceae are separated on the basis of the gynoecium and resulting fruit types. Refer to your lecture notes, handouts, your Text, Zomlefer, and Gleason & Cronquist for more details.

A. Oxalis sp. (Oxalidaceae - wood sorrel) (pp.272-274 [T], 136-139 [Z])

B. Salix discolor (female) and S. nigra (male) (Salicaceae - willow) (not in [T], pp. 114-116 [Z])

C. Euphorbia corollata (Euphorbiaceae - flowering spurge) (pp. 269-270 [T], 107-110 [Z])

D. Acer negundo and A. platanoides (Sapindaceae or Aceraceae - boxelder and Norway maple) (p. 289 [T], not in [Z]).

 

III. 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.

1. Lavatera trimestris (Malvaceae)
2. Hibiscus (Malvaceae - hibiscus)
3. Gossypium (Malvaceae - cotton)
4. Grewia occidentalis (Tiliaceae or Malvaceae now)
5. Cleome (Capparaceae)
6. Trapaeoleum (Tropaeolaceae - garden nasturtium)
7. Pelargonium (Geraniaceae - scented geranium)
8. Erodium (Geraniaceae - stork's-bill)
9. Oxalis (Oxalidaceae - sorrel)
10. Viola tricolor (Violaceae - pansy)
11. Cucumis sativa (Cucurbitaceae - cucumber)
12. Croton (Euphorbiaceae - croton)
13. Acalypha (Euphorbiaceae - chenille plant)
14. Ricinus communis (Euphorbiaceae - castor bean)
15. Vitis (Vitaceae)
16. Citrus (Rutaceae of Sapindales - citrus group)
17. Passiflora (Passifloraceae - passion flower)
18. Fuchsia (Onagraceae - fuchsia)
19. Ludwigia (Onagraceae - false loosestrife)
20. Oenothera (Onagraceae - evening primrose)
21. Cuphea (Lythraceae - cigar plant)
22. Punica (Punicaceae [now Lythraceae] - pomegranate)
23. Tibouchina (Melastomataceae - melastome)
24. Medinilla (Melastomataceae - melastome)
25. Melaleuca (Myrtaceae - bottle brush)
26. Eucalyptus (Myrtaceae - eucalyptus)

IV. 14 genera of Wisconsin plants to be able to identify on site.

Herbarium specimens of these plants will be marked to genus (and to family) and will be kept in the laboratory until the next laboratory exam when you will be tested on them. Use Gleason & Cronquist as much as possible to understand why each genus is different from other genera in the same family. This will help you not only to identify the plants to genus and family, but might be necessary as we will test you with different herbarium sheets of these plants!

1. Viola (Violaceae - violet)
2. Echinocystis (Cucurbitaceae - wild cucumber)
3. Salix (Salicaceae - willows)
4. Hesperis (Brassicaceae or Cruciferae - Dame's rocket)
5. Euphorbia (Euphorbiaceae - spurge)
6. Malva (Malvaceae - mallow)
7. Juglans (Juglandaceae - walnut)
8. Quercus (Fagaceae - oak)
9. Betula (Betulaceae - birch)
10. Geranium (Geraniaceae - wild geranium, crane's-bill)
11. Oxalis (Oxalidaceae - wood sorrel)
12. Vitis (Vitaceae - grape)
13. Toxicodendron (Anacardiaceae - poison sumac, poison ivy)
14. Oenothera (Onagraceae - evening primrose)

 

V. Key these plants to species using the Gleason & Cronquist. This kind of question might well be on a laboratory exam.

a. Identify to family and then to species [Hint: note the fruit type]
b. Identify to family and then to species [Hint: note the "inflorescence" type]