Taxon Report

Nemacladus twisselmannii J. T. Howell var. botanywomaniae Morin & T. J. Ayers

Botany Woman's threadplant

Print Report

Taxon Summary

Nemacladus twisselmannii var. botanywomaniae, commonly known as Botany Woman's threadplant, is a annual herb in the Campanulaceae that is found only in California. It occurs within Chaparral, growing at elevations from 1170 to 1215 meters. Nemacladus twisselmannii var. botanywomaniae is ranked 1B.1, Plants Rare, Threatened or Endangered in California and Elsewhere; Seriously threatened in California.

Classification


Scientific Name:	Nemacladus twisselmannii J. T. Howell var. botanywomaniae Morin & T. J. Ayers
Common Name:	Botany Woman's threadplant
Family:	Campanulaceae
Element Code:	PDCAM0F0D1
USDA Plants Symbol:
Synonyms/Other Names:

Ecology and Life History


Lifeform:	annual herb
Blooming Period: Apr(May)	Apr(May)
Elevation:	1170-1215 (3840-3985)
General Habitats:	Chaparral
Microhabitat:	Sandy
Microhabitat Details:	Sparsely distributed on sandy flats in or immediately adjacent to gently sloping washes in deep, quartz-rich sand in the desert transition zone.

Conservation Status


CA Rare Plant Rank:	1B.1
Global Rank:	G1T1
State Rank:	S1
State List:	None
Fed List:	None
Other Status:
CRPR Changes:	added to 1B.1 on 2023-04-26

Occurrence Data from the CNDDB


Total Occurrences:	2
Element Occurrence Ranks:
Excellent (A)	0
Good (B)	0
Fair (C)	0
Poor (D)	0
None (X)	1
Unknown (U)	1

Location


California Endemic: False
California Counties and Islands: Name (Code)
San Diego (SDG)
Quads: Name (Quad Code)
Tubb Canyon (3311624)

Threat List Data from the CNDDB


Threat List Total:	2
EOs with Threat Listed:	Total EOs	% of EOs
	2	100 %
Non-native plant impacts	2	100%
Erosion/runoff	1	50%

Notes




Threats:
Threatened by non-native plants, fire suppression activities (foot traffic), and erosion
Taxonomy:
Similar to but disjunct from var. twisselmannii and found in different habitat at lower elevations; differentiated morphologically by its non-resupinate flowers and deltate sepals

Selected References

Proposed addition to CRPR 1B.1, G1 / S1 (2023)

Madroño 67(1): 35–60 (2020)

Citation California Native Plant Society, Rare Plant Program. 2025. Rare Plant Inventory (online edition, v9.5.1). Website https://www.rareplants.cnps.org [accessed 5 November 2025].