The syllabus for Paper II of UPSC Botany Optional Subject is as follows:

1. Microbiology and Plant Pathology:
- Structure and reproduction in bacteria, fungi, and viruses.
- Principles of plant pathology including the classification, symptoms, and control measures of plant diseases.
- Principles of microbiology including microbial metabolism, growth, and nutrition.

2. Cryptogams:
- Classification, morphology, and reproduction of algae, fungi, lichens, mosses, and ferns.
- Economic importance of algae and fungi.

3. Phanerogams:
- Morphology, anatomy, and reproduction of gymnosperms and angiosperms.
- Taxonomy, economic importance, and ecological adaptations of gymnosperms and angiosperms.

4. Plant Physiology:
- Water relations of plants including absorption, transpiration, and water movement in plants.
- Mineral nutrition including the role of macro and microelements in plant growth and development.
- Photosynthesis, respiration, and plant growth regulators.
- Plant movements and plant responses to environmental factors.

5. Plant Breeding and Genetic:
- Basic principles of plant breeding including selection, hybridization, and mutation breeding.
- Techniques and methods of plant breeding.
- Mendelian genetics, linkages, and chromosome mapping.
- Cytoplasmic inheritance, sex-linked inheritance, and genetic engineering.

6. Economic Botany:
- Economic importance of plants including food crops, fiber crops, timber-yielding plants, medicinal plants, and ornamental plants.
- Biotechnology and its applications in agriculture and industry.

7. Biotechnology:
- Principles and applications of biotechnology in agriculture and industry.
- Genetic engineering techniques, genetic transformation, and gene cloning.
- Biotechnology and its impact on society, ethics, and biosafety issues.

8. Ecology:
- Basic principles of ecology including the organization of ecosystems, energy flow, and nutrient cycling.
- Population dynamics, community ecology, and ecosystem ecology.
- Conservation biology and environmental pollution.

Overall, Paper II of UPSC Botany Optional Subject covers a wide range of topics related to microorganisms, plant classification, plant physiology, plant breeding and genetics, economic botany, biotechnology, and ecology. It is important for candidates to have a thorough understanding of these topics to excel in the examination.