Biophytum sensitivum, commonly known as the sensitive plant or touch-me-not, is a fascinating and unique plant species belonging to the family Oxalidaceae. It is native to tropical regions of Asia, particularly India, and is known for its ability to rapidly respond to touch or physical stimuli by closing its leaves. This plant is a popular choice for those who appreciate interactive plants and want to add a touch of novelty to their indoor or outdoor gardens.

Description:
Biophytum sensitivum is a small perennial herb that typically grows up to 30-60 cm in height. It has delicate, fern-like leaves that are compound and pinnate in structure, consisting of several pairs of leaflets. The leaflets are oval-shaped, with a smooth texture, and have a vibrant green color. When touched or subjected to any movement, the leaflets fold inwards and droop, giving the plant its characteristic "sensitive" or "shy" appearance. The leaves reopen within minutes once the stimulus is removed. The plant also produces small, inconspicuous white or pale pink flowers, followed by tiny seed capsules containing several seeds.

Care Guide:

1. Light Requirements:
Biophytum sensitivum thrives in bright, indirect light. Place the plant near a window that receives filtered sunlight. Avoid exposing it to direct sunlight, as it can scorch the delicate leaves. If grown indoors, ensure the plant receives at least 4-6 hours of bright light per day.

2. Temperature and Humidity:
This plant prefers warm temperatures between 65-85¬?F (18-29¬?C). It is not frost-tolerant and should be protected from temperatures below 50¬?F (10¬?C). The ideal humidity level for Biophytum sensitivum is moderate to high, around 50-70%. If the air is dry, mist the plant occasionally or use a humidifier to maintain the desired humidity level.

3. Watering:
Keep the soil consistently moist but not waterlogged. Water the plant when the top inch of soil feels dry to the touch. Avoid overwatering, as it can lead to root rot. During winter or the plant's dormant period, reduce the frequency of watering, allowing the top few inches of soil to dry out between waterings.

4. Soil:
Biophytum sensitivum prefers well-draining soil. A mixture of peat moss, perlite, and regular potting soil in equal parts provides a suitable growing medium. It is also advisable to add organic matter, such as compost or leaf mold, to enhance soil fertility and water retention.

5. Fertilization:
Feed the plant with a balanced, water-soluble fertilizer diluted to half strength every two weeks during the growing season (spring and summer). Avoid fertilizing during winter or the dormant period. Overfertilization can lead to excessive vegetative growth but reduced sensitivity to touch.

6. Pruning:
Regular pruning helps maintain the plant's shape and encourages bushier growth. Trim any leggy or damaged stems to promote new growth. Pinching off the tips of the branches also stimulates branching and results in a fuller plant.

7. Propagation:
Biophytum sensitivum can be propagated through seeds or stem cuttings. To propagate from seeds, collect mature seed capsules, allow them to dry, and gently crush them to release the seeds. Sow the seeds in moist soil and cover lightly. Keep the soil consistently moist and provide warm temperatures for successful germination. For stem cuttings, take 3-4 inch cuttings from the plant's healthy stems and place them in a well-draining rooting medium. Maintain high humidity and provide bottom heat for quicker rooting.

8. Pests and Diseases:
Biophytum sensitivum is generally resistant to pests and diseases. However, it may occasionally be susceptible to aphids, spider mites, or mealybugs. Inspect the plant regularly and control any infestation promptly using organic insecticidal soap or neem oil. Ensure good air circulation around the plant to prevent fungal diseases.

In conclusion, Biophytum sensitivum is an intriguing and interactive plant that brings a touch of whimsy to any garden or indoor space. With proper care and attention to its specific needs, this plant can thrive and provide endless entertainment with its unique leaf-folding response to touch.