Thingia
{{Short description|Genus of flowering plants}}
{{Speciesbox
| image = Cistanthe ambigua 4.jpg
| genus = Thingia
| species = ambigua
| parent_authority = Hershk.
| authority = (S.Watson) Hershk.
| synonyms_ref = {{cite POWO |id=77210609-1 |title=Thingia ambigua |access-date=22 October 2023}}
| synonyms =
Species synonymy
{{Species list|
Calandrinia ambigua| (S.Watson) Howell|
Cistanthe ambigua| (S.Watson) Carolin ex Hershk.|
Claytonia ambigua| S.Watson|
Calandrinia sesuvioides| A.Gray
}}
}}
Thingia is a monospecific genus of flowering plant in the family Montiaceae comprised only by the species Thingia ambigua, known as desert pussypaws. It is native to northwestern Mexico, California, and Arizona,{{cite POWO |id=77210608-1 |title=Thingia |access-date=19 November 2023}} and is found commonly on sandy or silty soil.{{Cite web |title=UC/JEPS: Jepson Manual treatment for CALANDRINIA ambigua |url=https://ucjeps.berkeley.edu/cgi-bin/get_JM_treatment?6318,6319,6320 |access-date=2023-10-22 |website=ucjeps.berkeley.edu}} The sole species of the genus has been housed under several genera before it was split into Thingia: Claytonia in 1882, Calandrinia in 1893, and Cistanthe in 1990. DNA evidence demonstrated that the relationship of Thingia ambigua, then Cistanthe ambigua, to the next closest relative in Cistanthe, C. tweedyi, was actually disjointed. It was found that the two species were most closely related to completely separate South American taxa.{{Cite journal |last1=Hershkovitz |first1=Mark |last2=Zimmer |first2=Elizabeth |date=2000 |title=Ribosomal DNA Evidence and Disjunctions of Western American Portulacaceae |url=https://www.researchgate.net/publication/12457370 |journal=Molecular Phylogenetics and Evolution |volume=15 |issue=3 |pages=419–439 |doi=10.1006/mpev.1999.0720 |pmid=10860651 |bibcode=2000MolPE..15..419H |via=ResearchGate}}
Description
Thingia ambigua is an annual plant with fleshy roots. It has stems {{convert|3|-|18|cm|in|1}} long that grow outwards and upright. Its leaves are narrow and clasp the stem at their base; each leaf blade is {{convert|1.5|-|6|cm|in|1}} long. It has dense clusters of flowers, each with 3–5 white petals. They have 5–10 stamens with a yellow-colored anther and three stigmas with a pedicel that is {{convert|0.1|-|0.3|cm|in|2}} long. The seeds are oval-shaped and black in color. The species flowers from November to February.{{Cite web |title=Cistanthe ambigua in Flora of North America @ efloras.org |url=http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=242415714 |access-date=2023-10-20 |website=www.efloras.org}}
The genus has several distinctive characteristics that differentiate it from closely related taxa. It has three carpels, instead of the two possessed by species of Calyptridium and Philippiamra. While species of Lenzia also have three carpels, their foliage differs from that of Thingia. Plants of Thingia have leafy stems and complex flower structures, whereas those in Lenzia have almost no visible stems and only solitary flowers. Another difference is in the veins of the leaves: Thingia has a three-dimensional vein arrangement, where the veins of the other genera are arranged in a two-dimensional pattern.{{Cite journal |last=Hershkovitz |first=Mark |date=2020 |title=CORRECTIONS TO PHYTONEURON 2019-77: VALIDATIONS OF NAMES OF NEW TAXA |url=https://www.phytoneuron.net/2020Phytoneuron/42PhytoN-MontiaceaeCorrections.pdf |journal=Phytoneuron |volume=42 |pages=1–2}}