Describe the distinguishing features of each organism described in the lab exerc

Question

Describe the distinguishing features of each organism described in the lab exercises

22.3 Moniliophyta 1:

22.4 Moniliophyta 2:  

22.3 Phylum Moniliophyta, Subphylum Sphenophyta: Horsetails (About 15 min.) During the age of the dinosaurs, tree-sized representatives of this phylum flourished. But like the dinosaurs, they too became extinct. Only one genus remains. However, the remnants of these plants, along with others that were growing at that time, remain in the form of massive coal deposits. Speno-, a Greek prefix meaning "wedge," gives the phylum its name, presumably because the leaves of these plants are wedge shaped. A single genus, Equisetum, is the only living representative of this subphylum. Different species of Equisetum are common throughout North America. Many are highly branched, giving the appearance of a horse's tail, and hence the common name. (Equus is Latin for "horse"; saeta means "bristle.") Horsetails are very unlike what we often think of as ferns, but molecular evidence confirms their relationship to more typical ferns. MATERIALS strobilius Per lab room: Equisetum, living, preserved, or herbarium specimens with strobili Equisetum gametophytes, living or preserved leaves at node PROCEDURE branches 1. Examine the available specimens of Equisetum (Figure 22-7). Depending on the species, it will be more or less branched. 2. Note that the plant is divided into nodes (places on the stem where the leaves arise) and internodes (regions on the stem between nodes). Identify the small leaves at the node. If the specimen you are examining is a highly branched species, don't confuse the branches with leaves. The leaves are small, scale-like structures, often brown. (They do have vascular tissue, so they are true leaves.) Identify the leaves. Figure 22-7 Sporophyte of the horsetail, 3. Look at the herbarium mount and identify the underground Equisetum (0.2x). rhizome that bears roots. 4. Examine both the aerial stem and rhizome closely. Do both have nodes? Do both have leaves? Which portion of Equisetum is primarily concerned with photosynthesis? Photo by J. W. Perry

Explanation / Answer

In 22.3, Moniliophyta 1 the given organism is 'Equisetum'. It exhibits the following features.

1. It has a sporophytic plant body.

2. As it is a sporophyte, it's body is differentiated into root, stem and leaves.

3. Though it is having all three parts it is a creeping plant with little erect plant body.

4. Stem is having underground rhizome like ginger or turmeric with upright aerial green branches.

5. The stem exhibits nodes and internodes on it. It is a jointed stem. The internodes are having longitudinal ridges and furrows and hollow interior.

6. The stem contains silica deposits in it. because of the presence of silica deposits, the stem becomes rough.

7. On the stem, the microphyllous leaves are present in whorls.

8. After some level of maturation, the fertile branches bear strobili.

9. From the underground rhizome, adventitious roots are developed.

10. All spores are of same sized , so the plant is homosporous.

11. The spores give rise to gametophyte formation. from these gametophyte antheridia and archegonial sperm and egg cell fusion embryo is formed, which gives rise to sporophytic plant body.

12. Asexual reproduction is carried out by fragmentation of rhizome, like in potato tubers are formed on rhizome.

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