Botany/Plant reproduction laboratory flower

Chapter 5. Plant Reproduction Laboratory ~ Flowers

Infloresence of the orchid, Spathoglottis plicata (enlarge to examine).

An orchid flower

This first laboratory exercise for Chapter 4 deals with the flowers of a ground orchid from Southeast Asia. The photograph on the right demonstrates the descriptive terminology that can be applied to this species. You may wish to read about orchids to place this plant taxonomically and better understand unusual aspects of the structure of this flower. In reading the description below, be sure you understand how or why each bolded word applies to this specimen. Also, observe that the flowering-through-fruiting sequence is well demonstrated in the photograph because each flower is in a slightly different phase of its life cycle from bud to fruit.

Spathoglottis plicata Blume — The flowers of this orchid are carried on an erect raceme growing out of the pseudobulb, each flower subtended by a green to purplish bract that becomes strongly reflexed with age. The purple sepals and petals are similar and spreading, elliptic to elliptic-ovate; the labellum is in three distinct parts: the lateral lobes narrow and erect, the middle lobe horizontal and cleft or 2-lobed. Lying above the latter is the narrowly clavate column. The inferior ovary in Spathoglottis develops into a cylindrical capsule (fruit) as the perianth withers.

4-1. Review the photograph of the inflorescence of the orchid. Which one of these statements is true:

a) this inflorescence demonstrates determinate growth

b) this inflorescence could as well be called a spike

c) the uppermost flower shows anthesis.

d) there are five petals, therefore this is a dicot.

Photograph 1: Bidens torta (Examine)

Following are a series of photographs of flowers from various plants. Note that by clicking on the word "Examine" in each title, you can enlarge the particular photograph for closer examination. Read each question and the offered answers carefully. All parts of answer choice must be correct for that choice to be correct.

4-2. The structure at B is:

a) leaf

b) corolla

c) ligule

d) sepal

e) petiole

Photograph 2. Hibiscus (Examine)

4-3. Although the flowers in these three photographs appear very different, the following parts or floral structures are essentially the same:

a) AA and F

b) BB and C

c) G and H

d) F and B

e) D and BB

4-4. Which statement of the following applies to the structure indicated at E :

a) Pollen grains have landed on this pistil

b) Androecium of a monoecious plant

c) This is a spathe

d) E is an anther releasing pollen

e) This flower head is on a dioecious plant

Photograph 3. Xanthosoma or 'Ape (Examine)

<< Return to Chapter 5

Answers to Chapter 4 Laboratory Questions:

4-1 ~ c (this flower alone is capable of pollination)

4-2 ~ b (A flower head with tubular disk corollas)

4-3 ~ d (both F and B indicate petals of their respective flowers)

4-4 ~ d (the androecium is supported on a tubular structure (G) that surrounds the pistil (H)