Plant Species of the Borrego Desert: Campanulaceae

Nemacladus twisselmannii
var. botanywomaniae
Botany Woman's Threadplant

Fig. 1. Top: Two plants of Nemacladus twisselmannii var. botanywomaniae, Botany Woman's Threadplant, amidst typical small sand grains, showing two color variations of the plants. All flowers are in fruit except for the single flower in the picture on the right with the white petals. The flowers and fruit are typically 3 mm in length; these entire plants are just 6 mm (~1/4 inch) tall. The plant we vouchered was among the largest plants, at 13 mm tall and 24 mm wide (1/2 in tall and 1 inch wide). Photos by Keir Morse; see also photos below from 2012; photos from Keir from 2012 and photos from Fred Melgert and Carla Hoegen from 2019.

Bottom: Kate Harper, aka Botany Woman, pointing at two clusters of largish plants, also marked by white arrows; photo by Wayne Armstrong.

Click on photos for larger versions.

Table of Contents


Origin and Meaning of Name
Distinguishing Characteristics and Similar Species
Pictures of Young Plants, Mature Plants, and Dead Plants
Habitat, Distribution and Abundance


On 28 April 2012, as part of a floristic survey of the Wilson Trail area at Pinyon Ridge near 4000 feet elevation by all the authors, the first author was exploring a small sandy wash to look for Nemacladus and other similar diminitive plants. N. longiflorus var. breviflorus was found and recognized immediately, but there was a much smaller plant next to it that did not look like anything we had ever seen before (See picture with caption given below).

Examination with a hand lens revealed what looked like a Nemacladus flower, but we had no idea which species it was. In the field, we scanned the illustrations in the Jepson Manual. The plants strongly resembled the illustration of N. twisselmannii, but we summarily rejected that determination, since N. twisselmannii is an extremely rare plant known only from a single small area in the southernmost Sierra Nevada 210 miles away, at a much higher elevation of 7350 feet.

At home that night, we were absolutely flabbergasted when we compared our pictures to Nemacladus Pictures by Nancy Morin, and our plants were a perfect match to N. twisselmannii.

This is just about as implausible a find and determination as one could ever imagine.

N. twisselmannii is among the rarest plant species in California. There are only two known populations, from an area of less than ten total acres, in northernmost Kern County north of Lake Isabella (Isabella Lake on the USGS topographic map), containing a total of about 400 plants. They grow in a completely different habitat, an open mostly barren area on a steep rocky slope with a deep cover of decomposed granite and granitic sand in the pine forest, than the flat sandy wash in the desert transition habitat here. The description of the habitat is from the type voucher and topotype voucher.

Yet we could find no other determination, and Nancy Morin immediately kindly confirmed the determination. Nancy commented:

For me the defining characteristics include the really big ovary that seems to be in fruit almost before the flowers have had a chance to do much, the hairs all over the plant (nothing else in Nemacladus has hairs like this), and of course the very compact plant. N. t. shares with N. californicus the rosette producing an axillary stem making another rosette, which is almost never seen in N. t. because the plants rarely get big enough to create another stem. It is fascinating that these axillary stems in your plants have such long internodes, too. The calyx lobes look to be shorter in your plants than in the Pine Flat location.

We cannot even imagine how this species could be found in two such different localities separated by 210 miles, unless there are overlooked populations elsewhere. It would be extremely easy to overlook populations of this species, so it is difficult to say that there are not populations elsewhere.

We spent 30 minutes looking for enough plants (20) so that we could voucher one. Pictures of that vouchered plant are below. The plant we vouchered was among the largest plants around, at 13 mm tall and 24 mm wide (1/2 in tall and 1 inch wide), and had fruit and flowers.

We searched for additional plants on subsequent trips in 2012 and 2013, and found a total of 94 plants at three locations in 2013 from four separate searches. Searches in 2015, 2016, 2017, and 2020 found zero plants, even though 2017 and 2020 were good rainfall years. In fact, late rainfall might be harmful to these plants if it results in flooding that resurfaces the washes in which they live after they had germinated.

Thirty mostly tiny (even for this species) plants were found in April 2019, which was a very good rainfall year. But there were many very tiny plants of other species growing in the washes with them. These tiny plants probably germinated after the wash had been resurfaced during the normal growing season, which removed plants that had germinated earlier in the year. Plants that germinate late in the growing season usually end up producing just one or a few flowers on very small plants.

In a Madrono paper published in 2020, Nancy Morin and Tina Ayers decided that the plants here were sufficiently different from the N. twisselmannii plants in Kern County that they named our plants as a separate variety, var. botanywomaniae, a name suggested by the first author and strongly supported by the second author.

Origin and Meaning of Name

From Michael Charters' California Plant Names: Latin and Greek Meanings and Derivations:

From the Madrono paper:

The variety is named for Kate Harper, Senior Consulting Botanist and Wildlife Biologist, Harper Biological Consulting, who saw the plants first. She has been part of a group that has been documenting the plants of Anza Borrego Desert State Park for many years. When advised that the authors wished to name the plant for her in recognition of her discovery, she requested that the epithet be the name by which she is known in the group, which is Botany Woman.

Distinguishing Characteristics and Similar Species

No other Nemacladus looks even remotely like N. twisselmannii; all you need to do is a picture match using Nemacladus Pictures by Nancy Morin.

From the Madrono paper:

Nemacladus twisselmannii var. botanywomaniae differs from var. twisselmannii in having the flower non-resupinate, sepals broadly deltate, and occurrence in desert habitat.

"Resupinate" means that the flower pedicel is twisted to present the flowers "upside down" from how they would appear if there was no twist to the pedicel. Hence var. botanywomaniae does not have a twisted flower pedicel.

Pictures of Habitat,Young Plants, Mature Plants, and Dead Plants

Click on pictures to get larger versions

The photos below are all by Tom Chester and Kate Harper. See also 17 additional photos of these and other plants nearby from Keir Morse.


The plants were originally found in this small section of a flattish open sandy wash around 2 m (6 feet) wide. Keir Morse is studying one of the first plants found, in an area that had about ten plants. The foreground area, with a pink ribbon in it, contains a few additional plants. For these, and all pictures shown below, click on the picture to get a larger version.
These pictures show additional views of the same wash as above.

Young Plant Pictures

Mature Plant Pictures

Size comparison to Nemacladus longiflorus var. breviflorus (the larger plant on right). The N. twisselmannii (Plant 1 in the numbering scheme used here) is the almost completely-invisible gray smudge just touching the pen in the lower left of the picture. An unusually-colored Lasthenia gracilis is on the left side of the picture, and a small Erodium cicutarium in fruit at upper right. The pen is 13.5 cm long.

Plant 2.
The color difference between rows 1 and 2, and rows 3 and 4, is due to the use of a flash in rows 3 and 4.

Plant 3

Plant 4

Plant 5

Plant 6

Plant Group 7 (Two Plants)

Plant Group 8 (Two Plants)
The color difference between rows 1 and 2 is due to the use of a flash in row 2.

Vouchered Plant

Voucher after two days of pressing:

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Dead Plant Pictures

No dead plants have ever been relocated.

Habitat, Distribution and Abundance

The N. twisselmannii var. twisselmannii plants at their location in the Greenhorn Mountains apparently appear only sporadically, being absent in a number of years, and always observed in the same small spot when they are present.

Sporadic appearance also appears to be the case for our ABDSP plants, too. Here is a timeline for when plants were, or were not, observed. Years are separated by horizontal lines.

Summary. As of the end of 2020, plants were observed in only three years, 2012, 2013 and 2019. No plants were observed in two years, 2016 (a low rainfall year) and 2017 (a good rainfall year), even though the search was made at an optimal time. No checks were made in two years, 2014 and 2018, because they were low rainfall years, and no check was made at the right time in 2015, despite it being a decent rainfall year. Anza-Borrego Desert State Park was closed at the optimal search time in 2020 due to the novel coronavirus epidemic.

This area burned in a very large fire in August 2012. The discovery year was just before the fire; all subsequent surveys were post-fire.


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Copyright © 2012-2020 by Kate Harper, Tom Chester, Keir Morse, RT Hawke and Shaun Hawke.
Commercial rights reserved. Permission is granted to reproduce any or all of this page for individual or non-profit institutional internal use as long as credit is given to us at this source:
Comments and feedback: Kate Harper
Updated 7 June 2020.