Apiaceae creepy dead England english Finished flower flowerhead giant hogweed Great Britain head Heracleum mantegazzianum invasive macabre natural nature plant spent stem Sussex toxic umbel umbellifer wild Apulia background fennel Foeniculum foliage Gargano green herb italian Italy leaves Puglia texture Umbelliferae vegetable flowers pattern petals South Downs summer white Alexanders edible flowering plant perennial roadside Smyrnium olusatrum spring Suffolk yellow abundance abundant Bedfordshire damp field landscape many meadow profusion riverside cliff coast coastal Cornish cornwall fresh New opening