These are lilies as they appear in the wild, untouched by human hand, and they are some of the most beautiful lilies in the world and in the garden. If you haven't grown species lilies, I would highly recommend you try. That is not to say that I don't like the hybrids. I do. I have 'Stargazer' and 'Casa Blanca' and 'Muscadette' and 'Scheherezade' and many others and they're all "wow" plants when they're in bloom. But there is something about the classic, wild beauty of a species lily that the hybrids, no matter how beautiful, can't match.
One of my favorites is pictured here--Lilium henryi var. citrinum. The "henryi's", in general, are easy to grow. The type species is a soft but rich orange color, petals strongly reflexed and covered in dark brownish-purple spots. There is also a hybrid known as 'White Henryi' whose flowers are less reflexed and are white with a tawny orange throat and little to no spotting. But it is var. citrinum that I like most. I like yellow, so it's a shoo-in in my book.
It is a robust grower, but I must admit, it absolutely has to be staked. No exceptions. As lovely as it is, its stems are a little on the weak side, but nothing that a sturdy bamboo stake won't rectify. That will turn some of you off, I know, but gardening is not without some work and staking is one of the least time consuming and most important of tasks once you learn to do it properly, and some plants are just worth it. Believe me, there are plenty of floppy plants that I've sent packing to the compost pile over the years, but there are some I make exceptions for.
The bulbs of Lilium henryi var. citrinum can grow to a very large size--one of the largest of the traditional garden lilies--occasionally weighing in at over 3 pounds and measuring over 2 feet in circumference (around, not diameter!). I threw that tidbit in to warn you that if you choose to grow the "henryi's" to use caution when staking. You don't want to drive your bamboo stick through the bulb!
Other species that are at the top of my "favorite lilies" list include: Lilium speciosum var. rubrum, Lilium regale, Lilium leichtlinii, Lilium pardalinum (the "leopard lily", native to California and the west coast, but performs exceptionally well in other locations), Lilium canadense, Lilium wigginsii (aka Lilium pardalinum supsp. wigginsii) and of course, many others. If you love lilies and you haven't grown some of the species, do a quick Google search and I'm sure you'll find some to fall in love with!