A few key terpenes are often detected at high levels in and around cannabis grows, yielding scents that may be piney, grassy, citrusy, woody, floral, or earthy. The skunky odor commonly reported to emanate from mature cannabis plants is attributable to sulfurous compounds. Images, clockwise from top left: © Svt/stock.adobe.com; © iStock.com/luca gavagna; © Geoffrey Kuchera/Shutterstock.com; © iStock.com/Leslie Lauren; © iStock.com/phet phu.