Lilium parryi, Lemon Lily, Fact Sheet Expanded

This page elaborates on some of the information given in the Lemon Lily Fact Sheet, and gives sources.

Life cycle of a Lemon Lily in Pictures

Fig. 1. The life cycle of a lemon lily.

Top row. Left: fresh seeds. Right: First year plants, each with a single leaf.

Second row. Left: Probably a second year plant, with three leaves. Right: A very old plant (the munchkin lemon lily) which just produced five basal leaves due to drought conditions.

Third row. Left: A third year or older plant without enough resources to bloom, producing just a vegetative stem. Right: A very small plant producing a single flower. The leafy part of the stem is ~20 cm (8 inches); the entire plant is ~30 cm (12 inches) tall. Single-flowered plants are the most common flowering plants, but are usually more robust than this plant.

Fourth row. Left: An older plant (~10 years?) with ten flowers. Such plants are uncommon, at roughly 1% of the flowering population. Right: An older plant in fruit.

Bottom row. Left: A seed capsule in the process of splitting open to release its seeds. It has already released seeds at its upper end. Right: Dave blowing on a capsule, showing that a gust of wind can easily disperse the seeds short distances. The seeds travel rapidly enough to produce streamers in this picture. During the exposure time of 1/40 second, the seeds traveled 5 to 8 times their diameter of ~6 mm, a speed of 1 to 2 m/s (3 to 6 feet/s = 2 to 4 mph). That speed is more than a factor of ten slower than the gust Dave produced.

Click on the pictures for larger versions.

Confusion of the common name between Lilium parryi and Hemerocallis lilioasphodelus, both known as "lemon lily". At one of the very first Lemon Lily Festival steering committee meetings a member of the Idyllwild Historical Society attended so that he could write a story in their quarterly newsletter. Unfortunately he only stayed a short time so that he could get the jist of what we were doing without asking any questions. It was obvious that he went home and did a search for lemon lily on his computer and proceeded to write a very flattering article about this group of nice people who were planning a new festival and intended to plant lilies in the creeks in Idyllwild. He then went on to described the lilies as Hemerocallis. This caused a huge headache for Dave since Dave had to wait three months until the next quarterly newsletter to get a correction.

Pictures Comparing Lilium parryi with Hemerocallis lilioasphodelus: Daylilies grow in large clumps with long strap-shaped blades growing from the base of the plant; lilies have a single stem with leaves along the stem.

Lilium parryi
Entire plantLeaves near base of plantFlowers from the side
Hemerocallis lilioasphodelus
Entire plantLeaves near base of plantFlowers from the side
Fig. 2. Top row: Lilium parryi photographs by Tom Chester from 26 July and 2 August 2011. Bottom row: Hemerocallis lilioasphodelus, pictures © 2008 by Dr. Amadej Trnkoczy, of plant in the wild from Slovenia, from Calphotos.

Click on the pictures for larger versions.


Demographics: The Arizona numbers come from NatureServe Explorer (Table 1 under the Ecology & Life History section).

Seed Germination and Development: Seeds can germinate in water, as well as in the ground. The radicle (young root) emerges first from the seed, which then turns into a bulblet before the first true leaf emerges. See Fig. 3 for photographs of the germination process.

Fig. 3. The germination process of lemon lily seeds.
Top left: hydrophobic seeds floating on a water surface in a San Jacinto Mountain creek immediately after dispersal.
Top right: the development of the radicle from seeds kept in water. Note that the seeds are no longer hydrophobic, with germinating seeds now below the water surface.
Bottom left: the first true leaf emerging from the seed from seeds kept in water, without the development of a bulblet.
Bottom right: the first true leaf emerging from the bulblet from seeds kept in a growing medium.
Click on the pictures for larger versions.

Pollinator: Davis studied the natural pollinators of California lilies in 1956, and observed, in the San Gabriel Mountains, only one pollinator for L. parryi, Hyles lineata, a sphinx moth, which was present at late dusk and night. He reported that "they are extremely few in number and no two were seen at one time, but rather at half to one hour intervals". Reference: Davis, J.S. 1956. Natural pollination of California lilies. Thesis, Claremont Graduate School, Claremont, California. Also reported in The Systematic and Geographical Distribution of Hawkmoth Flowers in the Temperate North American Flora, Verne Grant, Botanical Gazette, Vol. 144, No. 3 (Sep., 1983), pp. 439-449.

The Center for Plant Conservation also mentions Sphinx perelegans as a pollinator for L. parryi, but without giving a source for that report.

A camera set up to observe a lemon lily in bloom at the James Reserve captured two photographs of a sphinx moth approaching the flower: at 11:03 p.m. on 11 July 2013 and at 8:26 p.m. on 9 July 2013. Photos © Jennifer Gee.

For sphinx moths to pollinate our lemon lily plants in the San Jacinto Mountains, it appears they have to fly to higher elevations from their host plants at lower elevations, a distance of six to nine miles, since we've never observed a sphinx moth caterpillar anyplace in the pine forest here. They then have to fly back down to lower elevations to lay eggs on their host plants. That flight distance doesn't pose a problem to an insect that fly at a speed of 30 mph (50 km/hr) and detect a female pheromone from as much as five miles away.

Caterpillars of Hyles lineata have been observed in large numbers munching on primrose on Apple Canyon Road on May 23, 2020, and just above Hurkey Creek Park on 7 July 2019. Sphinx perelegans has no iNat observations anyplace closeby, so is unlikely to be the pollinator for our lemon lilies. There are iNat observations of it in the San Gabriel Mountains and San Bernardino Mountains.

The timing of the emergence of the adult sphinx moths is also critical. If adults live 10 to 30 days, there is not much room for error in pollinating lemon lilies, which bloom typically for a similar period, unless the adult moths emerge over a longer time interval (which they might well do, given the observations mentioned above). If the lemon lily bloom time, and the sphinx moth adult stage, get out of sync due to climate change, lemon lily fruit set will suffer.

Another photo from the James Reserve showed a hummingbird visiting the flowers in the early morning.

Lilies grown in a hardware-cloth-protected enclosure at the Idyllwild Nature Center all developed fruit, even though the openings in the hardware cloth are just 1/2 inch. No moths were ever trapped inside the enclosure, so either they can reliably squeeze through those openings; or the lilies are being pollinated by some other insect; or the lilies self-pollinate despite reports that they do not self-pollinate (which is probably unlikely).

Small insects are very frequently seen in the flowers in the daytime, but it is not known whether they effect pollination. See the following pictures: pix 1; pix 2; pix 3; pix 4; pix 5; pix 6; and pix 7.

When Dave first started giving lemon lily talks, it was hard to find good photos of the flowers without bugs crawling all over the flowers, which at the time Dave thought spoiled the pictures. But now Dave is very interested in seeing all the critters who visit the flowers!

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Copyright © 2018-2020 by Dave Stith and Tom Chester.
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Updated 14 November 2020.