Chenopodium watsonii

Chenopodium watsonii A. Nelson 
Bot. Gaz. 34: 362. 1902.


[Chenopodium HOME]
Etymology
 After Sereno Watson (1826-1892), American botanist and curator of the Gray Herbarium.
Description:

Stems erect or ascending to decumbent, branched from base, 1-4.5 dm, sparsely to densely farinose. 
Leaves aromatic; petiole 0.4-1.4 cm; blade broadly rounded-triangular to rounded-rhombic or ovate, 1-2.6 × 0.5-2.9 cm, base rounded or subtruncate or broadly cuneate, margins entire or proximal leaves with 1-2 teeth on each side at base, apex rounded to obtuse or acute or apiculate, densely farinose on both surfaces. 
Inflorescences glomerules in paniculate spikes, 14-24 × 2-3 cm, maturing irregularly; bracts leaflike. 
Flowers: perianth segments 5, connate into 0.3 mm tube; lobes ovate, keeled, 1-1.4 × 0.9-1.2 mm, apex acute to obtuse, farinose, enclosing fruit at maturity; stamens 5; stigmas 2. 
Achenes ovoid; pericarp adherent, usually strongly whitened, honeycombed. 
Seeds subglobose, 0.9-1.3 mm diam., margins obtuse; seed coat whitened, coarsely honeycombed. 2n = 18.
Distribution:

USA: AZ, CO, MT, NM, SD, UT, WY Mexico: SO
Synonyms:
 Chenopodium olidum S. Watson, Illegitimate, Proc. Amer. Acad. Arts 9: 95. 1874.
   not Chenopodium olidum Curtis, Fl. Londin. 6: t. 20. 1791.
Chenopodium dacoticum Standl., N. Amer. Fl. 21: 22. 1916.
Chenopodium watsonii f. glabrescens Aellen, Repert. Spec. Nov. Regni Veg. 26: 120. 1929.
Type:
 US 693399
Taxonomic Note:

The taxonomic characterization of Chenopodium watsonii has had a convoluted trajectory. After being described as C. olidum by Sereno Watson, Aven Nelson, corrects the pre-occupied invalid name and names it C. watsonii for Watson.

But is worth noting that of the specimens chosen by Watson in the description of C. olidum, most are not C. watsonii. Of Fendler’s cited collections only 721 (GH 00299137) and 725b (GH 00299136) are confirmed as C. watsonii. 718 (GH 00299138) of which there are only fruits in the envelope at GH, we have seen a duplicate in BM and the plant has linear leaves and is confirmed as C. pallescens as are the fruits at GH.

The sheet of Fremont 382 has two plants the right one 382 is C. berlandieri collected in California where C. watsonii has not been documented. The left one is in flower but the lanceolate leaves indicate that the plant is not C. watsonii. Neither are C. watsonii the specimens of 970 Hall and Harbour (GH 299139 and others). Wolf 258 we have confirmed as C. incognitum Wahl.

Rydberg took on this issue as well using Wolf 258, as paratypes of his new taxon C. wolfii, another pre-occupied name. Most of the specimens he cites for it, are C. atrovirens. (Contributions from the Rocky Mountain Herbarium IV in the Botanical Gazette 34:5, p.362 (1902) http://www.jstor.org/stable/246504)

Website Info:
 We thank all the Herbaria who have very generously have allowed us to display their images. All images with a RED outline were either provided by the linked Herbaria or given us access to their website to obtain such images, or they were scanned while on loan to us. Please see the credits and further information by clicking on the Herbaria acronyms. The specimens’ images without such red outline, were taken by us during our research visits.

All fruit and seed images have been taken with the Visionary Digital Microscope System, Dun, Inc. Palmyra, VA by Lee Simpson at San Diego State University.

Website development by Lee Simpson. Contact: sdsuherbarium@sdsu.edu


Map:




Habitat and Field Images

Type specimen:

Herbarium Sheet of
US 693399
W. H. Over 6175

Specimens:
Herbarium Sheet of
Note: Very Rarely the whitest pericarp is thinner, and the fruit appears darker.
US 1651276
Herbarium Sheet of
GH
Vestal & Vestal 1939


Herbarium Sheet of
RM 301563
Dorn 2999


Herbarium Sheet of
GH 299136
Herbarium Sheet of
US 753887
W.H. Over s.n., 8-20-1914

Metcalf 217
Herbarium Sheet of   Herbarium Sheet of
K 54
P 04970909


Barkley 14657
Herbarium Sheet of   Herbarium Sheet of
TEX-LL 53169
UC 747824


Lindley 819
Herbarium Sheet of   Herbarium Sheet of
SDSU 21466
SDSU 21467



E. Hall 1873
Herbarium Sheet of
Herbarium Sheet of
NY 00324319
NY 00537324



Herbarium Sheet of
Herbarium Sheet of
Herbarium Sheet of
Herbarium Sheet of
ARIZ 217045
Kaiser 1204
ASU 14455
Lehto 13696
ASU 43883
McLeod 670
ASU 247318
Makings 766


Herbarium Sheet of
Herbarium Sheet of
Herbarium Sheet of
Herbarium Sheet of
GH
Wahl 21929
GH, HUH 00037178
Powell 4
GH, HUH 00037177
Ward Exp 1845
MONT 33621
Hawkins


Herbarium Sheet of
Herbarium Sheet of
Herbarium Sheet of
Herbarium Sheet of
MONT 33623
Hawkins 648
MONT 50497
Philip South - Oct 9, 1956
NMC 33205
Carter 8143
NMC 34057
Anderson Sep 11, 1935


Herbarium Sheet of
Herbarium Sheet of
NMC 48382
Holmgren 7296
NY 00008475
J. C. Frémont s.n., 1845


Herbarium Sheet of
Herbarium Sheet of
Herbarium Sheet of
Herbarium Sheet of
NY 00990888
Lehto 11568
NY 00990891
Crawford 733
NY
Thornber s.n., 1912
RM 827648
Nelson 67096


Herbarium Sheet of
Herbarium Sheet of
Herbarium Sheet of
Herbarium Sheet of
RM 827649
Hartman 83739
RM 827656
Kostel 2640
UCR 31616
Sanders s.n., 10-3-1982
US 896626
Standley 13505





Website development by Lee Simpson. Contact: sdsuherbarium@sdsu.edu