Question:
Use the following dichotomous key to identify an irregular blue flower with five petals and a fruit that is a ripened flower ovary or follicle.
Dichotomous Key of Ranunculaceae
#1.
a. Fruit is a group of alkenes.............................. go to step 2
b. Fruit is a group of follicles..............................go to step 4
#2.
a. Petals are not present.....................................go to step 3
b. Petals are present............................................Ranunculus
#3.
a. The flower has 4 sepals.................................. Clematis
b. The flower has 5 sepals................................... Anemone
#4.
a. The flowers are regular..................................... Aquilegia
b. The flowers are irregular................................... Delphinium
The flower is a: A. Anemone B. Clematis C. Delphinium D. Ranunculus
Answer:
The species belongs to Delphinium genera.
Step-by-step explanation:
A dichotomous key is relatively simple to interpret. All you need to do is to:
- carefully observe your organism,
- know some technical terms or have a biological dictionary, and
- follow the descriptions.
The dichotomous key is going to lead you to the answer.
In the example, we have a plant species with irregular blue flowers and five petals. The fruits are a ripened flower ovary or follicles.
- Irregular flower: Term that refers to asymmetrical flowers that only have one plane.
- Follicle: Term that refers to dry dehiscent fruits originated from a flower with only one carpel. When mature, they open by the ventral suture.
So, let us begin, step by step. For each number, we are going to have two options (a and b). By knowing our organism, we need to decide which one is correct and follow indications.
#1.
a. Fruit is a group of alkenes.............................. go to step 2.
b. Fruit is a group of follicles..............................go to step 4.
We know that our fruit is a follicle. Option a is not correct (it is not a group of alkenes). Option b is the correct one. Knowing this, we must go to step four. ***Note: In the hypothetical case that the fruits were a group of alkenes, and option a was correct, we should go to step two, as indicated***.
#4.
a. The flowers are regular..................................... Aquilegia
b. The flowers are irregular................................... Delphinium
We know that our flower is an irregular one. So the correct option is b. This option leads us to Delphinium genera. Our species belongs to this taxonomic group. ***Note: In the hypothetical case that the fruit was actually a regular flower, and option a was correct, our species would belong to Aquilegia genera***