海草

1. Origins, structure, and basic meaning

• Structure: 海草 is read as かいそう and is a noun for seagrass, a marine seed plant rooted in sandy or other seabed.
• Basic usage: Seagrass swaying in shallow water appears in 浅瀬で揺れる海草, while seagrass rooted in sand appears in 砂地に根を張る海草.

2. Common pitfalls and similar expressions

• A rooted marine plant
  • Although it moves with the waves, the examples show that it grows rooted in the seabed.
• Difference from 海藻
  • The two spellings share a reading, but 海藻 denotes algae, while 海草 denotes rooted marine seed plants.