Little and large
Santa Cruz waterlily has strikingly beautiful lily pads up to two metres wide, with prickly undersides and wide, upturned rims.
The titan arum is a giant among plants, with a massive flowering structure that rises some three metres above the ground. Its flowering is rare and unpredictable, and always grabs the headlines.
Nymphaea thermarum is the smallest waterlily in the world, and the only Nymphaea to grow in damp mud rather than water.
Elephant ear taro is a massive aroid with a spectacular cluster of upwardly pointing, arrow-shaped leaf blades which can reach one metre in length.
A yam from Southeast Asia, India and China, Dioscorea wallichii has edible tubers that can grow to over one metre long.
Part of an ancient group of plants related to the ferns, this species eluded discovery until 2007, hence its Latin name eludens.
A ragged-leaved inhabitant of African desert, some tree tumbos are believed to be over 1,000 years old.
Giant by name and giant by nature, this huge Californian conifer is by volume the largest tree in the world.
A star of many Western films, the iconic saguaro cactus is a spectacular feature of the Sonoran Desert in south western North America.
This flowering plant does not photosynthesise, but depends on fungi instead for survival.