List: word usually written using kana alone

usually written using kana alone  noun  noun (generic) 

• Scirpus hotarui (species of bulrush)

rarely used kanji form  usually written using kana alone  noun  noun (generic) 

• pygmy hippopotamus (Choeropsis liberiensis)

usually written using kana alone  rare term  noun  noun (generic) 

• pygmy hippopotamus (Choeropsis liberiensis)

usually written using kana alone  rare term  noun  noun (generic) 

• electric eel (Electrophorus electricus)

usually written using kana alone  noun  noun (generic) 

• giant mottled eel (Anguilla marmorata), marbled eel

usually written using kana alone  noun  noun (generic) 

• Asian swamp eel (Monopterus albus)

usually written using kana alone  noun  noun (generic) 

• Arctic lamprey (Lethenteron camtschaticum)

rarely used kanji form  usually written using kana alone  noun  noun (generic) 

• Far Eastern brook lamprey (Lethenteron reissneri), sand lamprey

usually written using kana alone  noun  noun (generic) 

• birch tree (esp. the Japanese white birch, Betula platyphylla var. japonica)

usually written using kana alone  noun  noun (generic) 

• double weeping rosebud cherry (Prunus pendula)