The disadvantage of the artificial system are given below
i) This system uses only a few superficial characters(i.e, habits, numbers, colors and shapes of leaves, etc) Which lead to many organisms grouped togeather.
ii)They considered mainly the vegetative characters or  the androecium characters as given by Linnaeus.cters i

The sporophytes bear sporangia that are subtended by leaf-like appendages called sporophylls. In some cases, sporophylls may form a distint compact structure called strobili or come. The sporangia produce spores by meiosis in spore mother cells.

Mosses are widely distributed from the Arctic through the tropics to parts of Antarctica. The gametophytic plant body is with leafy axis and shows a radial symmetry. The rhizoid are multicellular, branched and have oblique septa. Sex organs, i.e., antheridia and archegonia are usually borne in groups at the apices of reproductive branches. The sporophyte is usually differentiated into foot, seta and capsule.

Red algae The photosynthetic pigments located in the chromatophores are chlorophyll-a, d and \(\alpha \), \(\beta \) -carotenes, xanthophyll and biliproteins.
Green algae   Chromoplasts contain chlorophyll-a, b, carotene and xanthophyll.
Brown algae The chromatophores contain chlorophyll-a, c and \(\beta \),  \(\alpha \)-carotnes and xanthophyll.

The characters used in natural system of classification are morphology, anatomy, reproduction, cell structure, behaviour and biochemistry. The similarity in large number of characters show kinship.
Examples 
(i) Monocotyledons have one cotyledon in their seeds and their leaves have parallel ventation.
(ii) Dicotyledons have two cotyledons in their seeds and their leaves have reticulate venation.

Bryophytes show alternation of generation.The main plant body is gametophyte.After fertilization of egg and spermatozoids,zygotes do not undergo reduction division and they produce a multicellular body called sporophyte.
Then some cells undergo division and produce haploid spores which germinate to produce gametophyte.

Leaf-like appendages are called sporophylls that bear sporangia.

Pinus gerardiana(chilgoza)

Equisetum stems

Fertilization is of siphonogamous type,i.e, the male gametes are carried to the archegonia through pollen tube in gymnosperms. In Cycas only, pollen tube functions as haustorium and fertilization occur by zoodiogamy.

Difference between homosporous and hetrosporous pteridophytes are given below

(i) Mosses Funaria, Polytrichum, Sphagnum
(ii) Liverworts Riccia, Marchantia, Porella, Pellia
(iii) Pteridophytes Selaginella, Adiantum, Dryopteris, Equisetum.

Important features of mosses
(i) Erect, radially symmetrical leafy body produced from filamentous or thalloid juvenile stage is called protonema.
(ii) They bear multicellular branched rhizoids.
(iii) Sporophyte contains large amount of green tissue and is partially dependent upon the gametophyte

A small orchid lives underground. it has a mycorrhizal association which help it in obtaining nourishment from decaying organic matter

Sporophyte is the dominant phase in life cycle of pteridophytes.

Mannitol and laminarin are considered as reserve food material in many brown algae species. These are complex carbohydrates.

The Cell wall of phaeophyceae is made up of cellulose which is usually covered by a gelatinous coating of algin. Algin is a hydrocolloid which has good water holding capacity.

It is due to pigments Chlorophyll - a and b.

Kingdom - Plantae includes unicellular members of green algae e.g., Chlamydomonas Chlorella

Seed lie naked or  exposed on the surface of megasporophyll

Horticulturists are interested in Ginkgo as it has natural immunity to several plant diseases.
Important features are as follow
i)The plant is a tall tree of upto 30 m height.
ii) Leaves - shaped.
iii) Leaves have furcate venation.
iv) Dwarf shoots of female plant bear distinct megasporangiate structures.
v) Endosperm of roasted seed is edible 
Horticulturists prefer to grow only male plants,as female plant give unpleasant smell.   

Characteristics of gymnosperms:
1. Gymnosperm plants have naked seeds, which means that their seeds are not covered within a fruit.
2. The plant body consists of intermediate to tall shrubs and trees.
3. The gigantic redwood tree that is Sequoia is among the world's tallest trees.
4. Tap roots make up the root network. Cycas' coralloid roots are connected for nitrogen-fixing with cyanobacteria.
5. The stem might be branched or unbranched.
6. Simple leaves (as in Pinus) or complex leaves (pinnate in Cycas).
7. The leaves are needle-like that have tough cuticles and sunken stomata.
8. These prevent the occurrence of water loss.
9. Gymnosperms have heterosporous spores.
10.These produce different types of spores: microspores and megaspores.

Protonemal cell of moss - haploid
Primary endosperm nucleus in dicots - triploid
Leaf cell of moss - haploid
Prothallus cell of ferns - haploid
Gemma cell in Marchantia - haploid
Meristem Cell of monocots - diploid
Ovum of liverworts - haploid
Zygote of ferns - diploid