Revisio specierum cratageorum, dracaenarum, horkeliarum, laricum et azalearum / 
E. Regel. 
<br/><br/> Repaged reprint from: Acti horti petropolitani, vol. 10, 1871, 64 p. 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Hawthorns--Classification.<br/>Dracaena--Classification.<br/>Horkelia--Classification.<br/>Larches--Classification.<br/>Rhododendrons--Classification.