Cryptogams consist _______, _______ and ________.

Explanation

**Step-by-Step Solution:**

1. **Understanding Cryptogams**: Cryptogams are a group of plants that do not produce flowers or seeds. They are considered primitive plants and are classified under the category of non-flowering plants.

2. **Categories of Cryptogams**: According to Echler's classification, Cryptogams are divided into three main groups:
- **Thallophyta**: This group includes algae, which are simple, non-vascular plants that do not have true roots, stems, or leaves.
- **Bryophyta**: This group consists of mosses and liverworts, which are small, non-vascular plants that typically grow in moist environments.
- **Pteridophyta**: This group includes ferns and their relatives, which are vascular plants that reproduce via spores instead of seeds.
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