alligator-pear avocado avocado-pear black butter-pear climacteric-fruit cultivar egg-shaped fertility fruit firm food fruit green guacamole Hass variety healthy kernel large-berry large-seed nutritious ovate pebbled-skin perennials persea-americana ripe rough seed soft tree wrinkled abundant angles appearances castor-beans castor-oil castor-oil-plant castor-seeds cluster clusters common cotyledons Euphorbiaceae fast-growing flower flowers foliage highly-toxic inflorescences invasive large large-leaves leaf leaves medicinal palm-of-Christ palma-Christi poison poisonous ricinus-communis seed-pods seedhead shrub shrubbery spiky-green-seed-capsule spiny surface surfaces textured textures toxic toxins vegetation wasteland-weed weed widespread ancient-plant Australia Australian burrawang cone cycad cycads dioecious erect firm-fronds glaucous hardy inedible macrozamia-riedlei pineapple-like-cones seed-cones waxy-coating Western-Australian zamia-palms zamias