(Editor's Note: This article was originally published on July 6, 2008. Your comments are welcome, but please be aware that authors of previously published articles may not be able to promptly respond to new questions or comments.)
Gloria Jahoda in The River of the Golden Ibis has described in detail the environment of Crinum americanum, the American hardy swamplily, along the Hillsborough River in Central Florida. [See Crinum americum in thumbnail.] It is rare that we have a detailed description of the native habitat of a plant we only know from gardens.
The Hillsborough begins in the Green Swamp, nine hundred square miles of central Florida wilderness where white ibises drift in the shadows over willow-bordered pools. From high water oaks grey Spanish moss trails softly. The stillness is broken by the songs of Carolina wrens in the thickets, by the insistent voices of leopard frogs, by the calling of rain crows on slow summer afternoons. The smells are acrid: tannin-stained sloughs and the sourness of the hydrogen sulfide and methane gases that rise when the mud is turned by the foot of some wild creature, by a rare canoe, by a storm. Pileated woodpeckers rap high in the pines in the drier places, where the ground rises a foot or two and bare sand shows under pinestraw that glistens rusty in a fitful swampland sun. The Green Swamp is a trackless place. Its milky clusters of crinum lilies spend their beauty unseen by men, and bobcats prowl the tangles unafraid. The world of the white ibises is, as yet, inviolate. When the light strikes their feathers through the canopy above, they shimmer in a blaze of gold. 
FIGURE 1. Crinum Augustum. Giant Spider Lily 'Queen Emma'.The genus Crinum is one of sixty genera within the family Amaryllidaceae. There are some 180 species within the genus Crinum. Crinum flowers do resemble those of their cousin the Christmas pot plant amaryillis - which also naturalize nicely in Southern gardens. But most crinums are much larger than amaryillis. Some can grow to 7 ft in height [see Figure 1]. The plants grow from large bulbs, which may be up to 20 lbs in size. So they are plants that can make a landscape statement. Crinums are often adapted to wet or aquatic environments as are the Southern swamplilies described above. Some species proliferate along streams and rivers, while a few are adapted to desert conditions.  Some species are quite hardy and have been grown as far north as Zone 5  Some species, such as crinum latifolium  have significant medical value.
The most complete discussion of crinums is at [5,6] www.crinum.org, the website of Les Hannibal in California. Hannibal undertook the systematic study and classification of crinums. Many images of the species considered by Hannibal are also represented at the Photo Gallery of bulbsociety.org.  Marcelle Sheppard in east Texas is currently one of the most knowledgeable experts on crinums. She has produced commercially important hybrids. Many crinums are photographed and described on Marcelle Sheppard's website, www.marcellescrinums.com . Another source of information and photographs of crinums is A. L. Sisk's amaryllids in Cultivation, at www.crinum.us. 
FIGURE 2 . Crinum ugandense. 'Cosa Rican crinum'.Crinum americanum, the Southern Swamp Lily (See thumbnail, upper right) is native* to Southern states: Texas, Louisiana, Arkansas, Mississippi, Alabama, Georgia, Florida, South Carolina, and North Carolina  Crinum fimbriatulum, Milk and Wine lily, Confederate lily [Figure 1] can be found growing in almost every yard here in West Alabama in this historic Southern town. But, its origin is Africa. 
FIGURE 3. Crinum fimbriatulum. Milk and Wine lily, Confederate lily.
How did African lilies wind up in Alabama? One explanation for the presence of African crinums throughout the Southern states is that they were brought on African slave ships.  An explanation that gives credance to this theory is the use of crinums in traditional African medicine both in Africa and in the United States. 
Recent DNA studies add another dimension to the story of how Crinum lilies got to be where they are. In a study of genetic sequencing published in 2003, Meerow, Lehmiller, and Clayton identified three clades or genetic groups of Crinum species. Meerow et al. state that earlier classifications which supported a number of sub-genera within the genus Crinum are not supported by the genetic data.
Their interpretation is that these genetic clades represent bioregional groups. Their genetic study indicates that all crinums originated in Southern Africa. American crinums, North African and tropicals comprise one of the clades. An early group represented by Crinum flaccidum appeared in Australia and today this species is considered to be endemic to central Australia.  A third group is made up of Madagascar, Australasian, Sino-Himaloyan, and Southern African species.
While various land bridges connecting Africa with other continents have been suggested as routes for the dispersal of crinums throughout the subtropical world, Meerow et al. suggest that the dispersal could have been made in large part by crinum seeds traveling on ocean waves. They point out that the seeds are salt resistant and capable of floating long distances without being damaged. The corky covering waterproofs the seed and protects it (see Figure 10).
FIGURE 4. Crinum peduncalatum. 'swamp lily'FIGURE 5. Crinum amoenum. FIGURE 6. Crinum procerum. 'splendens'
(Please click Crinum amoenum to see details of original Plant Files photo by TomH3787)
FIGURE 7. Crinum Stars and StripesFIGURE 8. Crinum x powelli FIGURE 9. Crinum Ellen Bosanquet
PROPAGATION. FIGURE 10. Crinum seeds.
Crinums may be propagated from seeds, from underground offsets from the main bulb, or from bulb cuttings. Not all crinums are propagated the same way, however.
Not all crinums set seed. According to Les Hannibal, "Few hybrids will set seed, but a number have viable pollen."  The general rule is that species are propagated by seeds, while hybrids are propagated by offsets from the main bulb. Andy Cabe  Curator of Horticulture, Riverbanks Zoo and Gardens. Columbia, S.C. describes a third method. He makes cuttings from the basal plate of the main bulb.
Werner Voigt's  instructions for sowing seed of Crinum campanulatum would hold for most aquatic crinum species.
According to Robert Archer of the National Herbarium in Pretoria, S.A., true crinum species rarely multipy by forming offsets. He suggests this method for germinating the seed:
Seeds are placed in a well-drained, sandy medium with plenty of compost and a slow-release fertilizer such as bonemeal, with regular watering and full sun. The high water content of the seed enables it to germinate after a week or two, even in dry conditions. Seed germination is hypogeal: the embryo stem is formed soon after release and in turn produces the cotyledon and radicle below the soil surface. Check to see that the young bulb is not pushed out of the soil. If seedlings are kept growing throughout the winter months, they will reach flowering size sooner. First flowering can be expected after three (C. macowanii) to eight years (C. graminicola). The plants perform best in a permanent position and, like any Amaryllidaceae, do not react well to any disturbance of the roots. 
Avon Bulbs, UK  provide planting instructions for the hybrid crinum, Crinum x powelli. Propagation is by offsets from the main bulb. Dig down carefully then separate the offset cleanly from the mother bulb. Dig the hole 12 inches deep and plant the bulb so that the tip protrudes at the surface.
Species Crinums are propagated by seeds produced in late summer. The seed should be as fresh as possible when collected and planted immediately. Here are the instructions for propagating seeds supplied with Plant Files photos by onalee for the Crinum asiaticum, the White Giant Crinum Lily. Acording to onalee (see Figure 10). Figure 11. Sprouted crinum seed.
"Plant when fresh by just pressing into soil: leave top above soil line. Keep damp, but not soggy and warm. Germination about 30 days."
Figure 11 shows a White Giant Crinum Lily bulbil/Seed that has begun to sprout. Onalee says, The "Leaf is pointed; root is rounded."
. . .
A note about "rescuing" heirloom plants from house sites or country road sides. Get permission. Many people think it is fun to spend an afternoon collecting plants from National Forests, pastures, or abandoned house sites and even houses where it seems no one is home. When you spot a plant, that you would like in your personal garden, consider if an offshoot, or seeds would not be as valuable to you as destroying the whole plant. Consider that it might be the last one on earth. Then ask, before you dig.
* The concept that a plant is native to, or endemic to a certain place is somewhat obscured by genetic analysis. In this case, genetic analysis shows that all crinims originated in Southern Africa, as the discussion will show.
Thumbnail. Crinum americanum. Southern Swamp Lily. American Crinum. alhanks. february 8, 2002. Plant Files.
Figure 1. Crinum augustum. Giant Spider Lilly, Queen Emma. PotEmUp. November 15. 2005. Plant Files. "Hotel landscaping. Wilea, Kauai".
Figure 2. Crinum ugandese. Puerto Rican crinum. aking. May 23, 2004. Plant Files. "Flower is short lived but spectqacular in the garden."
Figure 3. Crinum fimbriatum. Confederate Lily. Milk and Wine Lily. TulsaRose. July 19, 2006.
Figure 4. Crinum peduncalatum. swamp lily. gearge4tax/PotEmUp. May 3, 2000. "Limahuli National Tropical Botanical Garden - Ha'ena, Kaua'a, Hawaii."
Figure 5. Crinum amoenum. TomH3787. July 13, 2007. "Picture taken July 8th at Plant Delights Nursery, Raleigh NC".
Figure 6. Crinum procerum. 'splendens' Dave. May 3, 2004.
Figure 7. Crinum 'Stars and Stripes'. Cape Coast Lily. dutch lady. May 20, 2008. Plant Files "Naples Florida".
Figure 8. Crinum x powelli. raydio. October 20, 2006. Plant files. "A fine hardy "workhorse" of a Crinum. Very easy to grow and can bloom reliably even under poor cultivation."
Figure 9. Crinum Ellen Bosanquet. Calif_Sue. Sept 12, 2006. Plant Files.
Figure 10. Crinum asiaticum seeds. 'Giant white crinum spider lily. onalee.
"Seeds/bulbils for the Giant White Crinum Spider Lily. Plant when fresh by just pressing into soil: leave top above soil line. Keep damp, but not soggy and warm. Germination about 30 days."
Figure 11. Crinum asiaticum. White Giant Crinum lily sprouted seed. onalee. July 29, 2006. "White Giant Crinum Lily Bulbil/Seed that has begun to sprout - directions on how to plant a seed that has begun to sprout above ground or before planting. Leaf is pointed: root is rounded."
 Gloria Jahoda. Holt, Rhinehart and Winston 1973. the River of the Golden Ibis. Quoted at www canoeescape.com
 Crinum. wikipedia.org
 Amaryllids in Cultivation. Crinum. A. L. Sisk. http://www.crinum.us/
 Crinum latifolium. wikipedia.org
 A systematic revision of the genus crinum. L. S. Hannibal. crinum.org
 The Genus Crinum (Amarylledaceae) descriptions and photographs. crinum.org
 Gallery of the Worlds Bulbs. crinum. bulbsociety.org
 Marcell Sheppard. marcellescrinums.com
 Amaryllids in cultivation 2005-2008. http://www.crinum.us/
 Crinum americanum, Southern Swamp Lily, Native to Southern states: Texas, Louisiana, Arkansas, Mississippi, Alabama, Georgia, Florida, South Carolina, North Carolina. Plants.USDA.gov
 Milk and Wine Lily, Confederate lily, Crinum fimbriatulum. doofus.org/Crinum See Figure 52, according to the classification offered by Hannibal.
 Cemetery Lilies. The Journey from Africa to Carolina. lushlifegarden.com/cemetery
 C.W. Fennell and J. van Staden. Abstract. Crinum Species in Traditional and Modern Medicine. Journal of Ethnopharmacology. Volume 78, Issue 1, November 2001, Pages 15-26.
 Alan W. Meerow, David J. Lehmiller, and Jason R. Clayton. Phylogeny and biogeography of Crinum L. (Amaryllidaceae) inferred from nuclear and limited plastid non-coding DNA sequences. Botanical Journal of the Linnean Society, 2003, 349-363. bulbsociety.org.pdf
 Recommended Native Plants for Alice Springs. Crinum flaccidum. Alice Springs Town Council. alicesprings.nt.gov.au
 Les Hannibal. Crinum Hybrids. www crinum.org
 Andy Cabe. Propagation of crinum by cutting the basal plate. www bulbsociety.org.
 Werner Voigt. Crinum campanulatum. Kirstenbosch NBG. October 2006. plantzafrica.com
 Crinum. Robert H. Archer. National Herbarium, Pretoria. September 2004. plantzafrica.com
 Avon Bulbs, UK. Planting Instructions. avonbulbs.co.uk