angled angles botanical-gardens clouds columnless-glasshouse conservatories conservatory conservatory-complex construction controlled- temperature curved curves curving dome domes energy-efficient flower-dome foliage garden gardens glass glasshouse greenhouse heating high-tech horticultural horticulture hothouse indoor-gardens light lighting optimized-conditions overcast palm-trees palms plants shrubbery shrubs Singapore steel structure sustainable-building-technologies transparent trees ventilation visibility warm-growing-environment windows abundant appearances castor-beans castor-oil castor-oil-plant castor-seeds cluster clusters common cotyledons Euphorbiaceae fast-growing flower flowers highly-toxic inflorescences invasive large large-leaves leaf leaves medicinal palm-of-Christ palma-Christi poison poisonous ricinus-communis seed-pods seedhead shrub spiky-green-seed-capsule spiny surface surfaces textured textures toxic toxins vegetation wasteland-weed weed widespread abstract appearance background blue-crown-passionflower blue-passion-flower caerulea climber close-up colorful coloring colors colourful colouring colours common-passionflower cultivar cut edible evergreen flora food fruit garden-flower green greenery hardy hardy-passionflower open ornamental ornamental-passionfruit Passiflora passiflora-caerulea passion-fruit passionfruit pith radial seeds skin strange tasty tendrils tropical-twining-vine unusual vigorous vine