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This blog meant to go up last week (woops) and I intended it to be slightly shorter, and well that failed. Well now it’s a bit later and I’m still obsessed with Mariposa Lilies, the topic of this week’s blog post. 

I started focusing on botany more intensely about two years ago, and only observed four species of the Genus Calochortus until this year. This year alone, from January 2021 till now husband Trevor and I have found 12 species. But we’ve got a ways to go to find all of them!

Genus Calochortus, greek for “beautiful grass,” are truly beautiful. The genera includes mariposas, also called mariposa lilies and others that go by the common name of globe flowers, cat’s ears and star tulips. While I find beetles and slime mold beautiful I think most people will universally agree that these flowers are something else! From the common Oakland Mariposa to the Callahan lily with it’s extremely small range, the diversity in color and size is incredible! But like quite a few other plant genera I haven’t sat down and tried to get to know her! What’s her taxonomic history? Who pollinates them? How many more species are out there to find? 

Range:

A Calflora search brings up 57 species (including varieties) that exist within California, but Calochortus extends to British Columbia and down to Guatemala with 67 total species. But 28 of the roughly 70 total species are endemic to California. They can be found in “deserts, grasslands, chaparral, meadows, vernal pools, springs, montane woodlands, and forest undrestores” according to a 2003 paper by Patterson and Givnish. What diversity of habitats, wow! 

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Life Cycle:

In general the cycle of a Calochortus throughout a year starts as a single basal leaf from its young roots, this leaf acts as the main photosynthetic organ. About six months weeks after the winter rains begin, the basal leaf starts growing and appears above ground, producing nutrients for the future structures through photosynthesis. When spring arrives in March/April the flower – technically an inflorescence – appears. Once pollinated, the fruit develops between April and June (species dependent). Once the seeds drop and disperse, the bulb chilling under the ground remains until the rains of winter return. Bulbs were actually collected and consumed by indigenous peoples of the Americas. 

I’d never read about bulb movement throughout a plant’s life until I was reading a 1987 paper by Fielder. She described that a young Calochortus bulb remains near the soil’s surface but steadily move downward to the dept of 10 cm-ish. They do so by using contractile roots, and once at it’s finally happy spot these roots are no longer produced. Oooo! How cool! Calochortus is capable of bulbifey, which is when these bulbs split–creating daughter bulbs, a form of vegetative reproduction. 

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So Taxonomy and Evolution. . .

Classification:

• Kingdom: Plantae (Plants) 
  • Phylum: Tracheophyta (Vascular Plants)
  • Subphylum: Angiospermae (Flowering Plants)
    • Class: Monocots
      • Order: Lilales (Lilies, Supplejacks, and Allies)
        • Family: Liliaceae
        • Subfamily Calochortoideae
          • Genus Calochortus 

In 1998 a phylogenetic analysis by T.B. Patterson helped categorize the genus into seven clades. These clades helped categorize species by cohesiveness within geographical and ecological factors. The final placements showed in general “mariposas [grow] in dry grasslands and semi deserts, star-tulips in wet meadows, cat’s ears in montane woodlands and fairy lanterns in closed forests” (eFlora, Patterson 1998). To which I can agree from my observations!

The same 2003 paper by Patterson and Givnish found “that limited dispersal led to the narrow endemism of individual species, geographic cohesion of clades, and parallel radiations in habitat preference, floral morphology [ how the plant looks], and serpentine tolerance [tough soil to grown on for most plants].” Basically this genera had “troubles” dispersing which led to the evolution of different species for the reasons listed. They termed this observation as “consequent radiation”. Let me try and break that down.

Lets start with one basic term, radiation. This is the process of organisms spreading out into a new environment. Consequent radiation is different than adaptive radiation, which occurs over time as organisms diversify and speciate when the environment changes, alterations in resource availability, and competition arises, or new ecological niches become available. In this case, species diverge apart becoming over time novel species (known as divergent evolution). Here consequent radiation is used to describe the process of Calochortus diverging from each other in different habitats rather than Calochortus diverging from others within the same habitat by evolving unique relationships with insects or in response to abiotic factors. In this type of radiation the researchers conclude that there was no “competition for key resources.” Only secondarily did “pollinators and abiotic conditions” play a role in the speciation of this genus we see today. These processes are why they found a pattern with Mariposas in dry grasslands where their bright colors aid in pollination attraction, verus fairy lanterns chilling in forests where their shape may help reduce damage from rain. Essentially limited dispersal combined with their ability to “radiate independently in the same area without hybridizing” were the driving forces of Calochortus becoming different species, whereas normally plants radiate out to different habitats and speciate. I hope I described the paper accurately; I’m rusty on my evolution paper reading skills. It’s fun to think about these things as it brings a new light and depth when out plant hunting.

Interestingly “tolerance to serpentine soil evolved independently a minimum of six times in Calochortus,” according to Patterson (1998). Serpentine soil is an uncommon soil, but familiar to botanists, especially in California as a select group of plants have evolved to thrive on the soil. Serpentine soil is produced by ultramafic rock which creates harsh conditions for plants because it lacks typically essential nutrients like nitrogen, phosphorus and potassium and contains lots of nickel and other heavy metals. So in six separate instances Calochortus plants evolved over time to grow on this otherwise very harsh soil. The species that did so are some of the rarer Calochortus. This shows why as an amatuer or pro botanist, you find yourself learning a bit of geology, something I’m working on. 

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Who likes to visit and who likes to munch oN these flowers? 

Hymenoptera and Coleoptera (beetles) are both known pollinators, along with bees, and thrips (Dilley 2000). While some plants have very specialized relationships with a particular insect, which is evidence of an evolutionary history and selection for achieving the most effective pollinator. But Dilley found in 2000 after sampling 25 species at 40 sites across Calochortus’ total range found multiple orders of insects visiting plants, and therefore they could be described as generalists. But pollinators did differ between species, even at the same site which suggests while some Calochortus species have narrowed the species of pollinators that come for a visit they haven’t reached specialization. . . yet. Maybe in a few millennia the story will be different, the beauty of evolution is it doesn’t stop! 

In terms of large wildlife that visit Calochortus, it’s usually to munch on the large basal (on or lowest to the ground) leaves. As you may recall this basal leaf that pops out of the ground to photosynthesize as much as possible is quite important to future success of the plant. This was confirmed by Fielder ( 1985, 1987) that indeed basal leaf grazing can indeed reduce the plants potential life span. Whose interested in such leaves? A 1988 investigation into a Idaho’s Calochortus species by Caicco found elk, mule deer, and depending on location multiple rabbit and pocket gopher species all like to take a bite or two.

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There are many other great papers on Calochortus metal accumulation and more taxonomy, but I’ll leave it here for now, otherwise I’d have trouble finding a stopping point! I hope you learned something new about the genus as I think they are both stunning and fascinating! But if you think there is a cooler lilly of California, go at it in the comments!

Happy Plant Hunting and Botanizing!

References: 

• Patterson, Thomas B., and Thomas J. Givnish. “Geographic cohesion, chromosomal evolution, parallel adaptive radiations, and consequent floral adaptations in Calochortus (Calochortaceae): evidence from a cpDNA phylogeny.” New Phytologist 161.1 (2004): 253-264. 
• Fiedler, P. L. (1985). Heavy Metal Accumulation and the Nature of Edaphic Endemism in the Genus Calochortus (Liliaceae). American Journal of Botany, 72(11), 1712. doi:10.2307/2443728 
• Fiedler, P. L. (1987). Life History and Population Dynamics of Rare and Common Mariposa Lilies (Calochortus Pursh: Liliaceae). The Journal of Ecology, 75(4), 977. doi:10.2307/2260308 Dilley, J. D., Wilson, P. and Mesler, M. R. 2000. The radiation of Calochortus: generalist flowers moving through a mosaic of potential pollinators. – Oikos 89: 209–222.
• Calochortus iNat About page
• eFlora of North America Calochortus page
• Serpentine Soil Wiki Page