Themidaceae 2023

[Robert]

The new growing season for Themidaceae (Liliaceae) in our part of Northern California begins with autumn precipitation and cooling temperatures. The above photograph of Brodiaea elegans ssp. elegans was taken in mid-February 2023 at our Placerville property. The new growth can be seen growing alongside last season’s dried flowering scape. Five species of Themidaceae grow on our Placerville property: Dipterostemon capitatus ssp. capitatus, Dichelostemma volubile, Triteleia laxa, Triteleia hyacinthina, and Brodiaea elegans ssp. elegans. A very short distance down the road from our property, Brodiaea minor can be found growing out of barren serpentine rock strata. Within our region many other species, subspecies, and ecotypes of Themidaceae can be found.

For those interested in acquiring more information on these species and other North American Bulbs, the 2001 publication “Bulbs of North America” is a good introductory text. The book is old and needs revision; however it is still a good source of general information for those that wish to know more about our native bulbous species. For those who are more interested in the taxonomy and botany, Jespon eFlora (ucjeps.berkekey.edu) and Calflora (calflora.org) are additional sources of information on the Themidaceae species in California. [Jasmin]: (And other flora native to our area, and California.)



There is a good degree of genetic variability in the populations of Brodiaea elegans ssp. elegans both in the wild, and in plants that we grow in our garden that are of interest to horticulture. One interesting characteristic is a deeper than average flower pigmentation.



In this seed pan the F2 generation of hybrid seed derived from the Select forms of Brodiaea elegans ssp. elegans are starting to germinate. Depending on the genetic make up of the parents, the F2 generation is likely to show a great deal of genetic recombination and variability.

[Jasmin]:  The Calflora website has many links to other native plant related organizations.  Some are involved in research, study, and restoration; however, there is also a compilation of companies that specialize in native plants and seeds.  Listed are a number of vendors we personally know, who have high integrity and quality, such as Seedhunt and Alplains.

[MarcR]

Robert,

Beautiful pictures!  [I wish I were able to use a camera again] You seem to be about 5 or 6 weeks ahead of me. We grow many of the same species.

[Robert]

Hi Marc,

You might not be in a position to take photographs, however your other contributions to the Forum are very much appreciated. 





Triteleia hyacinthina has a widespread distribution in Western North America. This species is common throughout much of California with populations extending northward to British Columbia and eastward into Idaho. This species is found in grasslands, especially vernally moist sites throughout its range. I have observed this species growing in shallow serpentine-based soils that are vernally quite hydric, but are exceedingly xeric during the summer and early autumn.

Pictured above is Triteleia hyacinthina growing on our Placerville property (blooming Mid-April). Here too the soil is serpentine based. The soil is composed of kaolinite clay, which can be quite dense in the lower strata of the soil profile, especially where the serpentine bedrock is at, or near, the soil surface. Percolation of water can be quite poor at these sites and this is often where Triteleia hyacinthina is found growing.

I have found Triteleia hyacinthina easy to cultivate in our Sacramento garden. It seems very tolerant of summertime irrigation. In addition, the plants are long-lived, non-weedy, and tolerant of both sun or part shade situations.



I found an interesting population of Triteleia hyacinthina growing in a seasonally snowmelt-flooded gravel bar at 5,500 feet (1,676 meters) in the Sierra Nevada Mountains. Although this species can be found growing within a wide altitudinal range on both the west and east side of the Sierra Nevada Mountains, this population is quite removed and isolated from other populations of this species.



The F1 seedlings derived from a seed accession from the above Sierra Nevada population have produced an excellent array of plants. The plants are compact and bloom profusely about 2 to 3 weeks later (early May) than my other seed accessions from locations at much lower elevations in the Sierra Nevada Foothills. Plants from the east side of the Sierra Nevada Mountain may produce plants that also bloom later in the season and have additional cold hardiness. Temperatures on the east side of the Sierra Nevada Mountains routinely drop below -18 C, or lower every winter, at times without snow cover.

Clearly I have only scratched the surface of the potential of these fine plants. A great deal of additional research is necessary.

[Maggi Young]

Hi Marc,

You might not be in a position to take photographs, however your other contributions to the Forum are very much appreciated. 

Indeed - that  goes for me too!

[MarcR]

Robert, and Maggi,

Thank you for your encouraging words!

Marc

[Robert]

Dichelostemma multiflorum is native from Southwestern Oregon to Northwestern California, southward through the Sierra Nevada Mountains and adjoining foothills with populations also reported in the Modoc Plateau region of California. Dichelostemma congestum is a similar but distinct species that shares much of the same geographic range and habitat. Both species have similar chromosome counts and I have observed possible hybrids in the field.

Pictured above is Dichelostemma multiflorum grown with a white Ixia species. This is an attractive plant combination in our garden. Most of my accessions of this species are from 5,000 feet (1,524 meters) in the Sierra Nevada Mountains. Here they are found growing in soils derived from ancient Mehrten formation andesite lahars, though I also have accessions found on soils derived from Calaveras Complex metamorphic rock.



Pictured is the emerging spring growth of Dichelostemma multiflorum as observed in the wild. Freezing weather and frequent snow accumulations are common during the late winter and early spring when the new growth emerges from the ground. Anthocyanin protects the susceptible new growth from excesses in solar radiation and extremes in temperature.



Occasionally I find very attractive dark foliaged forms of Dichelostemma multiflorum in the wild. Here this species can be seen growing with Viola purpurea ssp. integrifolia. Transcription factors govern gene expression of the anthocyanin in the leaf tissues. Some transcription factors respond to solar radiation: the more solar radiation, the more anthocyanin; shaded conditions little or no anthocyanin in the leaf tissues. Other transcription factors respond to temperature: cold temperatures more anthocyanin, warm temperatures little or not anthocyanin in the tissues. In some cases, the expression of the dark foliage continues regardless of temperature, and to a great extent in shaded locations.



From a 2015 seed accession I have been breeding for dark-foliaged plants. In this set of seedlings it is easy to see the various degrees of gene expression. The seedling on the right is completely dark-foliaged. With continued selection, good dark-foliaged plants with other desirable characteristics will be chosen.

[Robert]

Dipterostemon capitatus ssp. capitatus has been blooming in our Sacramento, California garden for the last 2 weeks. Now that the sun is out many more flower buds are starting to open. When I drive up to our Placerville property I see the wild stands of this species blooming on south facing banks at about 500 feet (152 meters) elevation. At 1,500 feet (457 meters) at our Placerville property no flowers have opened yet. Over night low temperatures are still dropping to 26 F (-3.3 C).

[Jasmin]:  Leave it to me, the wife, to contradict my husband.  On Monday, his brother Jim saw a Dodecatheon blooming.

[Robert]

Dipterostemon capitatus ssp. capitatus are at the peak of their blooming cycle in our Sacramento garden. I have several white forms of this species. The white forms generally are the first to start blooming each season, however this season they are late. The Dipterostemon pictured is blooming with Eschscholzia lobbii ‘Sun Dew’, Eschscholzia caespitosa, and a few late Narcissus species. This time of year this is a typical scene in our Sacramento garden. Dipterostemon capitatus ssp. capitatus is starting to bloom at our Placerville property at elevation 1,500 feet (457 meters). I will be taking photographs of this species in the wild tomorrow.



Triteleia laxa is also blooming much later than usual this year. The plants pictured are from a seed accession I made from Napa County, California. This form generally is the first to bloom each season. This year it is the last. Up at our Placerville property the flowers of Triteleia laxa have not opened yet. This is very late too.



Triteleia ixioides var. scabra is generally a mid-season bloomer, however here they are blooming with Triteleia laxa and Dipterostemon capitatus ssp. capitatus. Other seed accessions of this species have yet to start blooming. I will be curious to see what the wild populations of this species are doing in the foothills tomorrow.

[MarcR]

Robert,

Once again... Lovely display.

I grow many of thee same species.  Mine are coming soon.

[Robert]

Pictured, our Colusa County form of Triteleia laxa is being used effectively with other California native plant species. This is a very naturalistic scene with our native Salvia sonomensis, Arctostaphylos manzanita, and Allium species. The Alliums will bloom a bit later in the season.



This is the typically seen flower color of Triteleia laxa. This speces has an extensive range in California and there can be considerable genetic variability. As new selections and hybrids come to maturity we will share photographs of these plants.



Our F2 generation hybrids of Triteleia ixioides ssp. scabra are progressing well. The umbel-like inflorescences are well balanced with many flowers. This hybrid line is being crossed with another separate hybrid line, which will hopefully lead us closer to our goal.



When breeding, the flowers of plants in the Themidaceae family are generally very easy to work with. Pictured is a white form of Dipterostemon capitatus ssp. capitatus ready to be cross-pollinated.



This earlier hand pollinized flower of Dipterostemon capitatus ssp. capitatus was successful.

[Robert]

Tritelia hyacinthina is now coming into bloom in our Sacramento garden. Pictured is our Rocky Basin form of this species. This seed accession came from an elevation of 5,466 feet (1,666 meters). The range of this species extends into the eastern slopes of the Sierra Nevada Mountains. The climate in this region is quite cold during the winter, and forms from this region would likely be very cold hardy. This species can also be found in the lower foothill region on the west slope of the Sierra Nevada Mountains where summers are extremely hot and dry.

The flowers of some forms of this species can have an iridescent blue sheen that is both attractive and quite interesting. Triteleia hyacinthina is a highly adaptable species and well worth growing in the ornamental garden.

[Robert]

In our region of interior Northern California, Brodiaea minor is one of several late blooming Themidaceae species. This species is almost always found growing in nearly bare, soilless serpentine rock, often wedged in very tight crevices.



The bare exposed sites where Brodiaea minor is found growing experience intense solar radiation during the summer months. In addition, these exposed serpentine barrens are extremely dry during the summer and early autumn months. The vapor pressure deficit--a measure of aridity--is very high during this time period. The bulbs are dormant during this time period; however the plants can often experience relative extremes of heat and aridity during the winter and spring months.

These are very demanding environmental conditions; yet this species has proven to be quite adaptable to growing conditions in our Sacramento garden. Currently, I cultivate plants from two accessions in our region. One accession is from a serpentine barren located near our Placerville property at an elevation of 1,500 feet (457 meters). Our other accession is from another serpentine barren at an elevation of 2,500 feet (762 meters). This is near the high elevation limit for this species in our region.



Harvest Brodiaea, Brodiaea elegans ssp. elegans, is an extremely common species in our region. Its common name is very appropriate, as this species blooms when the winter grains such as wheat and barley are ripe for harvesting. This species is found over a wide altitudinal range in our area, from < 500 feet in the Lower Sonoran Foothills, to over 5,000 feet in elevation in the Sierra Nevada Mountains. When studied closely it is very apparent that this species possesses a great deal of genetic variability, some of which could be of horticultural interest.

Currently in our garden we have many seed accessions from a large range of differing habitats in our region. All are being assessed for horticultural potential.

Pictured above is a typical pale flowered form of this species.



Brodiaea elegans ssp. elegans as well as our other local Themidaceae are incorporated in our breeding and improvement project. Pictured is an F1 intraspecific hybrid of Brodiaea elegans ssp. elegans with very dark colored flowers. The F2 generation is progressing. In this instance, the plants are being selected for intense dark flower color, flower count per scape, poise of the inflorescence, general plant habit, and other characteristics. It will take many generations of breeding to bring out the best qualities of each characteristic we are selecting for.