In the sentence extracted from biomedical literature, identify all the chemical entities. The required answer format is the same sentence with HTML <span> tags to mark up specific entities. 
### Entity Markup Guides:
Use <span class="chemical"> to denote a chemical.

### Input Text: Tincture of Crataegus ( TCR ) , an alcoholic extract of the berries of hawthorn ( Crataegus oxycantha ) , is used in herbal and homeopathic medicine .
### Output Text:
<span class="chemical">Tincture of Crataegus</span> ( <span class="chemical">TCR</span> ) , an <span class="chemical">alcoholic extract of the berries of hawthorn</span> ( <span class="chemical">Crataegus oxycantha</span> ) , is used in herbal and homeopathic medicine . 