ancient-plant Australia Australian burrawang common cone cycad cycads dioecious erect firm-fronds fruit glaucous hardy inedible large leaves macrozamia-riedlei pineapple-like-cones poisonous seed-cones seed-pods toxic toxins waxy-coating Western-Australian widespread zamia-palms zamias burn hazel burn nettle burn weed herb herbaceous perennial herbs itching leaf medical plant medication medicine natural nature nettle nettles pain painful plant plants stems stinging nettle sunlight sunshine urtica dioica