Cardamine Uncertainty: The Cedars form of toothwort; heart-shaped foliage marbled in black, silver and purple.

Got milkmaids?

 The lovely rhizome (corm) leaves of toothwort at The Cedars showing conspicuous marbling of silver and purple; the undersides of the leaves are always deep purple as is typical for species.

Most Californian plants take advantage of the winter rainy season to get started in their life cycles, but few complete the full process of growing, flowering and setting seed completely contained within these rainy months.  At The Cedars (Sonoma Co., CA) there are a few annuals that fit this pattern, and one showy perennial, California toothwort.

 

The flowers of toothwort are very early season, often appearing before December, but they are showy and cheerful, especially in the two months they have the flowering "field" to themselves.  They can be white or pink initially, but all turn darker pink to rose as they age.  On dry days they face outward or upward, but become nodding during rainy weather.  They close at night and stay that way on dark days.

The toothworts were formerly in the genus, Dentaria, the Latin name referring to teeth, and the roots of the European species were used medicinally for tooth-ache (another common name for this group in California is milkmaids, I assume due to some visual similarity).  A few decades ago, all the Californian species (as well as others) were re-assigned to the genus Cardamine (car DAM in-knee), a genus previously most known to temperate climate gardeners by popweed, Cardamine oligosperma, an annoying weedy pest whose seed capsules explode when ripe, flinging the seeds everywhere - often in the gardener's eyes.  While today it is considered a weed exploiting the human tendency to create disturbed soil, popweed was once native just to the Western US. There is actually one small spot within the canyon system of The Cedars where popweed is found; whether it was native to the site or brought in by human traffic is uncertain.)

 

A solitary juvenile plant on the left, a mass of dozens on the right.  The dreaded popweed, a common garden "pest" during the winter months.  It's short season from germination to exploding seed capsules can be as short as 8 weeks.  In dry gardens this is mainly a weed of the cool season, but in irrigated landscapes can be a problem year round.

 

Anthocyanins are dark pigments found in many plants such as the purple color of "red" cabbage, the purple of purple-leafed plums or eggplant skin, the blue of blueberries, the black of blackberries, etc. The race of toothwort at The Cedars seems to represent an enhanced anthocyanin version of the more widespread species (Cardamine californica).
 












Young growth often emerges and exhibits very dark, almost black coloration; seen above left in front of rock with leaf and new stem.  Right picture shows coloration persists into stem elongation and early flowering.

 Today in California - using currently published Floras - we have about 10 native toothwort species, each with one or many varieties; worldwide there are about 170 species.  However the way we look at and name our toothworts is changing.  In the future the new, The Jepson Manual II (JM II) and the Flora of North America (FNA), the author or these groups, Ihsan Al-Shehbaz, will be reducing to synonomy many names that we have been using in JM I.  According to Al-Shehbaz - lead author for the entire Brassicaceae or Mustard Family - in our area of the North Bay there will only be two choices, C. californica and C. nuttallii; C. californica being more southern, while C. nuttallii goes N into British Columbia.  But even using this highly reduced choice of  possibilities, the plants at The Cedars still seem ambiguous.

 
















Rhizome leaf, the first leaf to appear and typically different looking from the leaves on the flowering stems which emerge just afterward.  Both here show strong purple coloration in the upper leaf while the leaf on the right also shows the silvery character (rather than green).


Beyond the basic question of what is the best species name for this entity, there is the fact that the plants at The Cedars have characters not characteristic of either species - especially the pronounced leaf coloration/mottling characters shown in the pictures.  Before corresponding with Al-Shehbaz, I had thought I had hit on the answer, as I noticed that in the Sonoma Flora (Best et al, 1996) that C. pachystigma var. dissectifolia was listed as occurring in NE Sonoma Co. up N of Cobb Mt.  Looking up this entity online (CalPhotos, Plant Profiles and CalFlora), the pictures of both the species, C. pachystigma and its variety, dissectifolia, have the silvery, purple streaked/mottled leaves of those plants at The Cedars.  It didn't seem implausible to think that if this variety occurred in NE Sonoma Co., it could also occur in NW-Central Sonoma Co as a disjunction (separated range or distribution).  It seemed particularly plausible as both those entities have an almost exclusive occurrence on serpentine soils and rock - thus The Cedars seemed ideal.  Furthermore, several dozen other plants at The Cedars are disjunctions - thus this fit that "theme" perfectly.

The early foliage leaves (without stems) are almost always simple roundish or heart-shaped, though a few may have secondary leaflets.  This plants shows all the odd characters; dark coloration, splotching w purple, and silvery sheen on upper leaf.

But since in JM II, C. pachystigma will be restricted to plants with simple leaves on the stem (not 3 or 5-foliate as at The Cedars)  and its variety (v. dissectifolia) won't even exist (except as a synonym of C. pachystigma), this option is no longer a possibility as a name.  Since C. californica is so widespread in our area, it is perhaps enticing to place The Cedars toothwort into the more northern species, Nuttall's toothwort, however more features fit California toothwort than that species.  Thus we are left with considering it as just an exceptional form or race of California toothwort.

 Cluster of early rhizome leaves before flowering stem emerges.  Because there are no gophers in The Cedars, some plants can develop into substantial clusters.

As one drives into The Cedars, typical California toothwort is common in grassy meadows, oak savannah, and open woodlands for many miles - there is nothing unusual about this.  As soon as one enters the "hard" serpentine canyon of The Cedars though, one can immediately recognize that the plant has become different - more isolated individuals, shorter and stouter, thicker leaves with pronounced colorations on the upper surface, and more pink or rose pink flower color (some are white, but all age pink, while some start deep pink and age deeper).  It is clear that The Cedars entity is not only more obvious, it is bolder in nearly every visual feature.  To my eye, the plants remind me of the vigorous robust plants one would see in the first season of an area that has burned (the previous season) - sort of an exaggerated example of what the plant might more normally look like.  Here however, there has been no fire and these characters show up every year even in overgrown sites.

 












Some leaves have pointed tips on the lobes, others curl back.



So for now, it seems best to consider that these plants have gradually exaggerated certain features that exist in the widespread species, but which probably fit the habitats within The Cedars better.  The more pronounced anthocyanin throughout the plant suggests it has gone the same way that the Cedars' endemic purple-leaf stream orchid (Epipactis gigantea f. rubrifolia) has - producing a unique race characterized by this enhanced coloration.


Anthocyanin anyone?  The darkest plants would be interesting horticultural selections - however my previous experience trying to grow these at UCBG (Berkeley) suggest this race is challenging and impermanent in cultivation.
It must be kept in mind that the colorations in the young leaves mostly disappears at seed maturity, although some dark or silvery tones may persist - these are primarily juvenile characters, but are conspicuous through flowering, even early seed development.  Another caveat is that since these characters have appeared at The Cedars, it is likely that similar races may have appeared elsewhere in open rocky sites - it would be nice to hear of anyone else's experience finding or observing them, and whether they are the same or unique in some other manner.


Since the Cardamine at The Cedars flowers exclusively during the rainy season, the flowers have dealt with that fact by easily bending over, becoming nodding, when wet - thus avoiding water splashing into the sexual parts (anthers and stigmas) of the flowers.  I initially wondered if the plants were using some "cue" on rainy days to nod, but it appears most likely that simply the weight of water droplets on the flowers cause this "adjustment", as even a heavy nighttime dew will cause the flowers to bend downward.  As can be seen in the above photos, petal size varies considerably - though most are the larger/bigger form as on the right.

The flowers of the toothwort are sweetly fragrant up close (similar to wallflowers (Erysimum)), though my nose does not detect any fragrance from even a foot away.  In ideal sites - such as loose rubble and talus openings in woodland or chaparral, each clone will form a small colony from underground spread, each colony easily separable from its neighbors by its distinctive leaf coloration or flower color and form.  While asexual root reproduction is common, each plant is usually surrounded by numerous and variable-looking seedling plants - suggesting sexual reproduction is equally or possibly the more common means of regeneration.  Like its popweed relative, each ripe silique (seed capsules) will explode - flinging its seed widely.  Even a single previous-season's dried seed scape may be surrounded by dozens of seedlings; their variability showing that the leaf characters are re-sorted in each seedling generation.

I used to think that the toothwort in The Cedars pretty much occurred everywhere within this ultramafic (serpentine) geological unit, but I've noticed this spring that it is actually rather restricted - though abundant and showy in the right places.  It seems most profuse in open chaparral or cypress woodland that is very park-like, and on the lower, more stable talus slopes, or rocky ledges.  On the rocky talus slopes it is the most impressive, each plant often forming a sizeable colony of basal foliage and one to many flowering stems, somewhat like a bouquet sitting in the sliding rocks.  Each plant is different from its neighbors; one with very silvery foliage, one with nearly black foliage, one without any markings at all - and everything in-between.   It is one of the joys of visiting The Cedars in the winter months.  It can start flowering as soon as 6 weeks after the first rains in fall, but peak months are always January and February when little else is showy.

What this plant's unusual characters reinforce to me is the fact that The Cedars has once again "pushed" a plant into a unique or at the very least unusual set of features - maybe not enough to constitute a species, but obviously distinct to the human eye. The Cedars rules!

Is the leaf coloration some sort of camouflage?  I used to say that the foliage seemed like it was trying to match the silvery, reptilian coloration of serpentine.  However I have yet to see a leaf that "disappears" against its background to my sight.  Thus, to benefit the plant overall any theoretical predator would have to be searching primarily by eyesight and have poor eyesight as well.  But who know?



(P.S. anyone missing my excellent article on The Cedars in Fremontia, the journal of the Calfornia Native Plants Society (came out in Dec. but listed as April 09), should consider joining the organization to get a copy.  It will be posted on-line in a few months at their website if you want to wait.)