- Sub-Division A.—Myxomycetes, Slime-Fungi, with only 1 class.
- Sub-Division B.—Algæ, with 10 classes:
- Class 1. Syngeneticæ.
- „ 2. Dinoflagellata, Peridinea.
- „ 3. Diatomeæ, Diatoms.
- „ 4. Schizophyta, Fission Algæ.
- „ 5. Conjugatæ.
- „ 6. Chlorophyceæ, Green Algæ.
- „ 7. Characeæ, Stone-worts.
- „ 8. Phæophyceæ, Brown Algæ.
- „ 9. Dictyotales.
- „ 10. Rhodophyceæ, Red Algæ.
- Sub-Division C.—Fungi, with 3 classes:
- Class 1. Phycomycetes.
- „ 2. Mesomycetes.
- „ 3. Mycomycetes, Higher Fungi.
Division II.—Bryophyta or Muscineæ, Mosses. These have leaf-bearing shoots, but neither true roots nor vascular bundles. The lowest Mosses have, however, a thallus. Fertilisation is accomplished by means of self-motile, spirally coiled spermatozoids, through the agency of water. From the fertilised oosphere a “fruit-body” (capsule) with unicellular organs of reproduction (spores) is produced. The spore on germination gives rise to the vegetative system, which bears the organs of sexual reproduction; and this system is divided into two stages—the protonema, and the leaf-bearing plant produced on it.
Alternation of generations:
- I. The protonema and the entire nutritive system which bears the organs of sexual reproduction.
- II. The capsule-like sporangium, with spores.
- 2 Classes: 1. Hepaticæ, Liverworts.
- 2. Musci, Leafy Mosses.
Division III.—Pteridophyta or Vascular Cryptogams, Fern-like Plants having leaf-bearing shoots, true roots, and vascular bundles with tracheides and sieve-tubes. Fertilisation as in the Mosses. From the fertilised oosphere the leaf-bearing shoot arises, which bears on its leaves the reproductive organs, the spores, in capsule-like sporangia. From the germination of the spore a small prothallium is formed, which bears the sexual reproductive organs.
Alternation of generations:
- I. Prothallium with organs of sexual reproduction.
- II. Leaf-bearing shoot with capsule-like sporangia.
- 3 Classes: 1. Filicinæ, True Ferns.
- 2. Equisetinæ, Horsetails.
- 3. Lycopodinæ, Club-mosses.
Division IV.—Gymnospermæ. The vegetative organs are in the main similar to those in the 3rd Division; special shoots are modified into flowers for the service of reproduction. From the oosphere, which is fertilised by means of the pollen-tube, the leaf-bearing plant is derived; this passes the first period of its life as an embryo in the seed, and continues its development when the germination of the seed takes place. The organs corresponding to the spores of the two preceding Divisions, are called respectively the pollen-grain and embryo-sac. The pollen-grains are multicellular; i.e. they contain an indistinct prothallium. In the embryo-sac a prothallium, rich in reserve material (endosperm), with female organs of reproduction, is developed BEFORE FERTILISATION. The pollen-grains are carried by means of the wind to the ovules; these enclose the embryo-sac, and are situated on the open fruit-leaf (carpel), which has no stigma.
Alternation of generations:
- I. Prothallium = Endosperm in ovule.
- II. Leaf-bearing plant, with flowers which produce the pollen-sac and ovule.
- 3 Classes: 1. Cycadeæ.
- 2. Coniferæ.
- 3. Gnetaceæ.