Chapter 21.3, Problem 3MI

Summary Introduction

To define:

The given terms. 

Introduction:

The terms given in the questions are related to Pteridophytes. They are first land plants such as ferns. They have underground modified rhizome. They reproduce through spores produced in the sporangium.

Answer to Problem 3MI

The definition of the terms given below:

Terms	Definition
Strobilus	A compact cluster of spore-bearing leaves produced by some non-seed vascular plants.
Epiphyte	A plant that lives anchored to an object or another plant.
Rhizome	A thick, underground stem of a fern and other vascular plants; often functions as an organ for food storage.
Sporangium	A structure in ferns that forms spores.
Sorus, sori	Clusters of sporangia usually found on the surface of fern fronds

Explanation of Solution

A strobilus is a sporangia-bearing structure densely aggregated along a stem in many land plants such as ferns. 

An epiphyte is a plant which grows upon another plant or on any object. It grows to take only support. It is not like a parasite, orchids and ferns are examples of epiphytes.

A rhizome is a horizontal underground plant stem capable of producing the shoot and root systems of a new plant. 

A sporangium is a sac-like structure which contains spores. It is present in many plants.

Sorus, plural sori are brownish or yellowish cluster of sporangia usually situated on the lower surface of fern leaves.