Similar Species in Similar Families

Phacelia species. Oh, that blue!

Last year during my Death Valley trip, Cryptanthas drove me crazy. There are something like 120 different species, many of which can only be reliably distinguished by examining the minute nutlets.

Cryptantha species




I saw plenty of Cryptanthas in Anza-Borrego, too, and decided not to bother much with them. Neat little flowers, but I would just have to accept that I wouldn’t be able to identify them fully.

a different Phacelia




Then there were the Phacelias. I saw plenty of them, too. Turns out there are about 170 species of Phacelia in North America. Not all of them are found in the Sonoran Desert, of course, but enough of them are.

Phacelia crenulata.

Phacelia nashiana. Unless it’s Phacelia minor.

Like Cryptanthas, the Phacelias are notoriously tricky to identify. I spent hours poring over botanical descriptions but my pictures contain only so much information, and often not the right sort. I didn’t get very far.

A different Cryptantha; the flower is about 1 mm wide.



I gave up when I discovered that there’s a species named Phacelia cryptantha.

Phacelia campanularia. I think. I hope.






While researching these plants, I tripped across another issue. Seems that authorities don’t quite agree on which family to place the genus Phacelia in. At one time, there were two separate but closely related families, Boraginaceae (borage) and Hydrophyllaceae (water-leaf).

Pholistoma membranaceum, Hydrophyllaceae. Unless it’s Boraginaceae. Or the Hydrophylloideae subfamily of Boraginaceae.


Recent research has resulted in the Hydrophyllaceae being considered a subfamily of the Boraginaceae, called Hydrophylloideae.  Not all authorities recognize this distinction, though, and research is ongoing. It’s another one of those areas of taxonomic uncertainty.

Amsinckia species, either A. tessellata or A. intermedia, Boraginaceae

Emmenanthe penduliflora, Hydrophyllaceae. Or Boraginaceae. Whatever.













In an attempt to make sense of all this, I went through several books* to get good technical descriptions of the two families’ characteristics, and came up with this chart:

Boraginaceae Hydrophyllaceae
form: forbs; rarely shrubs or trees forbs; rarely subshrubs
overall rough textured, hairy overall small, hairy
leaves: alternate alternate; rarely opposite
simple simple, sometimes compound
no stipules no stipules
often entire mostly lobed, rarely entire
coarsely hairy often hairy or stiff-hairy
inflorescence: helicoid or scorpioid cyme scorpioid cymes or flowers borne singly
flowers: often blue or white mostly blue, purple, white
regular (radially symmetrical) regular (radially symmetrical)
bisexual bisexual
5 sepals, separate 5 sepals, separate or fused
or deeply cleft to appear separate or deeply cleft to appear separate
5 petals, fused 5 petals, fused, often w/ appendages inside
5 stamens fused to corolla, alternate with petals 5 stamens fused to corolla, alternate with petals
? nectary disk present
anthers w/ longitudinal slits anthers w/ longitudinal slits
2 carpels, united, often 2 lobed 2 carpels, usually united
locules 4, usually 1-2 locules
ovules 1 per locule ovules 2 – many
ovary superior ovary superior
style 4-lobed style 2-lobed
stigma 2 lobed stigma capitate
fruit drupe or nutlets capsule

I’m not sure it helped, but it was an interesting exercise.

Phacelia cryptantha?!


Speaking of Phacelias, three of them are native to the Maryland Piedmont. Yesterday I found one blooming profusely and one of the others budding up. More on them in a few days.

another Cryptantha!

Phacelia and Amsinckia growing together, the devils.

*Botany in a Day, Thomas J. Elpel
Contemporary Plant Systematics, 3rd. ed., Dennis W. Woodland
How to Identify the Flowering Plant Families, John Philip Baumgardt
Photographic Atlas of Botany and Guide to Plant Identification, James L. Castner

4 thoughts on “Similar Species in Similar Families

  1. Nice job.

    This sounds like a botanist paradise.

    Ambiguity between species is always a problem. Sometimes it may be impossible to tell the difference between different species at certain phenological stages.

  2. Pingback: A Special Phacelia | Elizabeth's Wildflower Blog

  3. Pingback: One More Phacelia | Elizabeth's Wildflower Blog

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