Rome is antiquity, divinity and Buon appetito. And Rome is crowds, graffiti, and exhaust fumes. But a trek through the Orto Botanico di Roma is a respite, where an unhurried stroll through the quiet greenery instills calm. With its visual and olfactory pleasures, Orto Botanico more than holds its own with Rome’s more popular park destinations like the elegant Villa Borghese, itself a worthy (and free) destination, and the pricey Vatican gardens tours. Covering just under 30 acres, the Orto Botanico sprawls upward from Rome’s Trastevere neighborhood to claim its place…