Moss stage - xerarch, Biology

Assignment Help:

Moss Stage - Xerarch

The accumulation of soil, particularly in the crevices and depressions of rock favours the growth of certain xerophytic mosses, e.g., species of Polytrichum, Tortula and Grimmia. The spores of these mosses are brought by the blowing wind. They have more or less the same power of withstanding desiccation as that of foliose lichens.

The lichens and mosses grow together and compete 'with one another. The rhizoids of mosses and foliose lichens compete for water and nutrients, and the stems of the former attain greater height than the latter. The plants in the lower strata, i.e., the lichens die, and the mosses grow. The mosses form cushion-like structure that may be a few centimetres in thickness. The substratum is thus gradually built up and is widened. The foliose lichens gradually give way to mosses that overtop the lichens. Many times, all three stages may be found on a single rock surface, the pioneers occupying the most exposed places.


Related Discussions:- Moss stage - xerarch

Hemoconcentration, Hemoconcentration Before, during and after CPB, hem...

Hemoconcentration Before, during and after CPB, hemoconcentration allows the patient's blood to be salvaged during surgery to help reduce the need for donor blood. Ultra

AUTOCHORY, ALL ABOUT AUTOCHORY?HOW IT WORKS

ALL ABOUT AUTOCHORY?HOW IT WORKS

Does every amino acid have a central carbon, Does every amino acid have a c...

Does every amino acid have a central carbon? To which organic group is that central carbon bound? A carboxyl group -COOH, an amine group - NH 2 , an atom of hydrogen -H and a v

Classes of life form, Classes of Life Form The five life form classes ...

Classes of Life Form The five life form classes are: Phanerophytes, Chamaephytes, Hemicryptophytes, Cryptophytes, and Therophytes.

How can a child become infected with gonorrhoea, How can a baby become infe...

How can a baby become infected with (a) gonorrhoea, (b) syphilis   (a)  During birth, a baby might be become infected with gonorrhoea bacteria as it passes by t

Effect of environmental factors-sexual reproduction, Effect of Environmenta...

Effect of Environmental Factors some lower organisms, though the genetic determiners of the sexes are present, the ambient environment plays a decisive role in the development

Determine the signs and symptoms of bulimia, Determine the Signs and Sympto...

Determine the Signs and Symptoms of Bulimia? 1. Binges, minimum twice a week for three months 2. Purging a Menstrual irregularities 3. Swollen glands Frequent fluct

Formation of cocoon in earthworm, Formation of cocoon in earthworm: I...

Formation of cocoon in earthworm: In earthworm segments from 14 to 17 are swollen. Skin on these segments is thick and glandular. This is called clitellum. When ovaries ma

How are lipids used as an energy source by the organism, How are lipids use...

How are lipids used as an energy source by the organism? Carbohydrates are the major energy source for aerobic cell respiration. In the absence or deficiency of such substances

Introduction to heart surgery, INTRODUCTION :  It took just hundred years ...

INTRODUCTION :  It took just hundred years for cardiac surgery to advance to what it is today. Before 1896, surgeons considered heart to be "inviolable" and it was stated that ope

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd