Plant Species of the Borrego Desert: Boraginaceae: Cryptantha species, Popcorn Flowers
This page, while accurate, only gave the state of my understanding of our Cryptantha species as of 2009. Since then, I've learned to distinguish nearly all of our Cryptantha species in the field, most of them at a glance, without the need to examine the nutlets in most cases. Hence this page will be superceded as I put photographs of each species online, with their distinguishing characteristics. See the new main page.
To add: links to simpson; how to distinguish the two most common species, angustifolia and barbigera.
Cryptantha species have a well-deserved reputation for being hard to distinguish, since the characteristics that separate the species are all minute, and few of them show up in a photograph of the flower. However, three of our species are distinctive enough that they can be immediately recognized in the field at a glance. Many of the other species can be distinguished by simple measurements of the width of the flower and the length of the calyx in flower and fruit. These measurements can easily be obtained from a photograph of the flowers from the side that also include a scale like one's finger. Only a few species require observations of the seeds (called nutlets).
None of our Cryptantha species are like the namesake of this genus, which had inconspicuous flowers that self-fertilized without opening, and thus was named from the Greek krypto, "to hide, hidden," and anthos, "flower," and thus meaning "hidden flower" (Charters 2009).
This page gives a key to distinguish the Cryptantha species in the Borrego Desert, along with a table of their key characteristics that can be used instead of the key to make determinations in the field. In the future, I'll add pictures that demonstrate each of the quantities used in the key, as well as pictures of each of our species to illustrating the key.
The table is often much easier to use than the key, since, for example, if one observes a flower width of 8 mm, one can quickly use the table to determine that it can be only one of two species, and the table shows how to distinguish them. Also, as in this example, one can use the table to get some identifications without ever looking at the nutlets.
Note that this key cannot be used anyplace other than the Borrego Desert, since other places may have additional species that key similarly to one of these species.
See also Version of the key and characteristics for printing, without the other text on this page.
Key to Cryptantha species
1. Perennial; plant bushy C. racemosa 1'. Annual (2) 2. Plant gen wider than tall; all flowers in axils of leafy bracts C. micrantha 2'. Plant taller than wide; flowers bracted or not (3) 3. Flower bracts present on at least some flowers (4) 3'. Flower bracts never present (5) 4. Flower width 0.5-1.5 mm; calyx length in fl 1-2 mm C. maritima 4'. Flower width 1-3 mm; calyx length in fl 3-4 mm C. costata 5. Nutlets winged (6) 5.' Nutlets unwinged (7) 6. Nutlet wings < 0.5 mm, entire C. holoptera 6'. Nutlet wings 0.5-1.0 mm, lobed at tip; calyx appearing inflated due to large wings C. pterocarya 7. Calyx length in fl 4-6 mm; calyx densely bristled near base C. barbigera 7'. Calyx length in fl < 4 mm (8) 8. Corolla width 1-2 mm (9) 8. Corolla width 1-8 mm (10) 9. Nutlets 1-2 C. ganderi 9'. Nutlets 4 C. nevadensis 10. One nutlet bigger than the others C. angustifolia 10'. Nutlets equal in size (11) 11. Nutlets 1(2); style < half nutlet length C. decipiens 11'. Nutlets (1-)4; style 0.9-1.3 x nutlet length (12) 12. Calyx length in fl 1-2 mm C. muricata 12'. Calyx length in fl 2-3.2 mm C. intermedia
Characteristics of Borrego Desert Cryptantha species
The following table is organized into groups of species with distinctive characteristics, in the following order:
- the four species with bracted flowers
- the two remaining species with winged or sharp-edged nutlets
- the single species with the largest calyx in flower of the remaining species
- the two species with the smallest flowers of the remaining species
- the single species that has one nutlet larger than the others
- the remaining three species.
Characteristics which distinguish one species out of its group are given in bold.
In some of the columns, an x means that characteristic is present, and an s means it is present in some plants or some flowers.
The Abundance column gives two numbers. The first is the number of the 24 areas in the Borrego Desert in which I have observed that species. A giant caveat goes with that number, since many of the 24 areas have not yet been surveyed at a time of year in which these species could be identified. The second is the number of the 11 regions in the Borrego Desert for which I have compiled vouchers. These numbers should just be used to indicate whether a species is common, like C. angustifolia, seen in 5 areas and 10 regions, and C. barbigera, 8 areas and 9 regions, or scarce, like C. nevadensis, 0 areas and 2 regions, and C. decipiens, 1 areas and 0 regions.
# nutlets Length
Abundance Other Cryptantha racemosa x x 0.5-2.2 1-2 2-3.5 gen 4 >>1 x 2/5 per Cryptantha micrantha x 0.5-6 1-3 2-3 (1)4 s s 1/8 plant gen wider than tall; root purplish Cryptantha maritima s 0.5-1.5 1-2 2-3.1 1-2 <= 1 x 7/6 Cryptantha costata s x 1-3 3-4 4-6 4 >1 x (s) 1/6 margin sharp-angled Cryptantha holoptera x 1-2 1-2 2-4 1-4 > 1 x 1/2 wings < 0.5 mm, entire Cryptantha pterocarya x 1-3 2-2.5 3.2-6 3-4 s 1/7 wings 0.5-1.0 mm, lobed at tip Cryptantha barbigera 1-8 4-6 5-10 1-4 ~1 x 8/9 Cryptantha ganderi 1-2 3-4 6-10 1-2 x 1/4 Cryptantha nevadensis 1-2 1.8-4 4-10 4 >~ 1 x 0/2 Cryptantha angustifolia 1-5 1-3.6 2.5-4 4 1.6 x 5/10 one nutlet bigger than the others Cryptantha decipiens 1-5 1.5-2.5 2-4 1-2 < 0.5 s x 1/0 Cryptantha intermedia 2-8 2-3.2 3.5-6 1-4 0.9-1.3 x 1/2 Cryptantha muricata 1-8 1-2 2-4.2 4(2-4) >1 x 1/4
Copyright © 2009 by Tom Chester.
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Comments and feedback: Tom Chester
Updated 10 February 2009 (bolded information at top of page added 29 December 2012, and file name changed to _old)