Week 8 Laboratory

Saxifragales and Rosids (part I)

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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. Rosa sp. (rose) (Rosaceae subfamily Rosoideae — Rosid) (pp. 275-279 [T], 181-185 [Z])

Rosa represents an example of the large, primitive subfamily Rosoideae

Vegetatively, the Rosaceae are defined by alternate, compound leaves with large stipules — find these

Note the epicalyx and identify the hypanthium

How many carpels are present? What kind of fruit(s) do you expect this flower to produce?

Compare the gynoecium and fruit of Rosa to demonstrations of the other three subfamilies of Rosaceae and be able to separate the four subfamilies

Give a floral formula for Rosa.


B.  Phaseolus (bean) (Fabaceae — Rosid) (pp. 262-265 [T], 160-165 [Z])

This legume is a representative of the more common faboid group within the family

Note the zygomorphic flowers — identify the banner or standard petal, 2 lateral petals, and the fused keel petals

Carefully find the 10 stamens. What is unusual about them? The term for this condition is diadelphous.

Locate the pistil within these stamens. How many carpels? The fruit produced from the pistil is a special follicle called a legume which opens along 2 lines.


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. Sedum (sedum, Crassulaceae – Saxifragales) (pp. 330-332 [T], not in Zomlefer)

B. Rosaceae (Rosid) (pp. 275-279 [T], 181-185 Z; see lecture handouts)

1. Spiraea (meadowsweet, Rosaceae subfamily Spiraeoideae).

2. Potentilla (cinquefoil, Rosaceae subfamily Rosoideae)

3. Prunus (cherry, Rosaceae subfamily Prunoideae)

4. Malus (apple, Rosaceae subfamily Maloideae)

C. Ficus (Moraceae - Rosid) - demonstration of syconium fruit (pp. 275-276 [T], 100 - 103 [Z]; note in some books (as in Z) the Moraceae and Urticaceae are combined under Urticaceae)

D. Cassia occidentalis (senna, Fabaceae, or sometimes Caesalpiniaceae - Rosid) (pp. 262-265 [T], 160-165 [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.

A. Kalanchoe (Crassulaceae - kalanchoe)
B. Rosa (Rosaceae - rose)
C. Ribes (Grossulariaceae - gooseberry, currant)
D. Mimosa (Fabaceae, or Mimosaceae - sensitive plant)
E. Cassia (Fabaceae, or Caesalpiniaceae - senna)
F. Arachis (Fabaceae - peanut)
G. Medicago (Fabaceae - alfalfa)
H. Lupinus (Fabaceae - lupine)
I. Ulmus (Ulmaceae - elm)
J. Pilea spp. (Urticaceae - creeping charlie, aluminum plant, Panamiga, artillery plant)
K. Urtica (Urticaceae - nettle)
L. Dorstenia (Moraceae - "fig' relative)
M. Ficus spp. (Moraceae - fig, rubber plant, creeping fig)


IV. 12 genera of Wisconsin plants to be able to identify on site (* = not presently found in Wisconsin).

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 your 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! S = Saxifragales; R = rosid.

1. Hamamelis (Hamamelidaceae -- witch hazel) S
2 . Ribes (Grossulariaceae -- gooseberry, currant) S
3 . Mitella (Saxifragaceae -- miterwort, Bishop's-cap) S
4 . Sedum (Crassulaceae -- stonecrop) S
5 . Potentilla (Rosaceae -- cinguefoil) R
6 . Prunus (Rosaceae -- cherry) R
7 . Rosa (Rosaceae) -- rose) R
8 . Lupinus (Fabaceae -- lupine) R
9 . Baptisia (Fabaceae -- wild indigo) R
10. Urtica (Urticaceae -- nettle) R
11. Ulmus (Ulmaceae -- elm) R
12. Cannabis (Cannabinaceae -- marijuana) R


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

a. Amelanchier (Rosaceae)
b. Desmodium (Fabaceae)