1. Nutlet attachment scar at tip of +- 0.5 mm angled narrow stalk, at inward facing (ventral) surface (sect. Echidiocarya)
2. Pl caespitose; st 0.2-0.8 dm, erect; infl short, +- hidden by lvs ......................................................................... P. collinus var. ursinus
2' Pl not caespitose; st 1-4 dm, prostrate to spreading; infl elongate, exceeding lvs
3. Corolla 4-8 mm broad; st hairs gen +- fine, soft .................................................................................... P. collinus var. californicus
3' Corolla 1--3 mm broad; st hairs gen coarse, +- rough
4. Nutlets 1.5-2 mm long; lf oblanceolate, 3-5 mm wide .......................................................................... P. collinus var. fulvescens
4' Nutlets 1-1.5 mm long; lf linear, 2-2.5 mm wide ....................................................................................... P. collinus var. gracilis
1' Nutlet attachment scar +- sessile, not on narrow stalk, on inward facing (ventral) surface to oblique positioned, or on short, +- basal
peg (much shorter than stalks in 1.)
5. Lower cauline lvs alternate, sometimes crowded occ +- paired, upper alternate; basal rosette present or 0; pl always taprooted; mostly occurring
in well draining soils; nutlet attachment scar on inward facing (ventral) surface near middle
6. Nutlet surface tessellate; attachment scar long, narrow, elevated along crest of keel (sect. Amsinckiopsis) ......................... P. jonesii
6' Nutlet surface not tessellate; attachment scar short, +- round to rarely oval, sunken below at base of keel (sect. Plagiobothrys)
7. Calyx gen circumscissile with sepal lobes gen curved inward over fr; st and lower side lf midveins and margins conspicuously reddish,
staining surfaces
8. Bracts 0-few, near base of infl; corolla (3)4-9 mm broad; nutlet slightly arched in profile ................................... P. nothofulvus
8' Bracts few-many, +- throughout infl; corolla 2-3 mm wide; nutlet gen strongly arched or folded in profile ........... P. arizonicus
7' Calyx rarely circumscissile with sepal lobes erect to +- spreading, rarely curved inward over fr; st and lower side lf midveins and
margins green or reddish
9. Nutlet attachment scar deeply concave, pit-like ..................................................................................... P. fulvus var. campestris
9' Nutlet attachment scar convex to rarely shallowly concave
10. Interspaces of nutlet back gen wide, flat, between narrow cross-ribs; nutlet not cross-shaped, narrowed at apex only
..................................................................................................................................................... P. canescens var. canescens
10' Interspaces of nutlet back gen narrow, groove-like, sometimes obscure, between wide, sometimes +- tubercled, cross-ribs;
nutlet +- cross-shaped, abruptly, +- equally narrowed near apex and base .............................................................. P. tenellus
5' Lower cauline lvs clearly opposite, upper gen alternate; basal rosette 0; pl initially fibrous rooted to rarely becoming taprooted; occurring in
poorly drained soils; nutlet attachment scar on inward facing surface near base, sometimes oblique, or basal (sect. Allocarya)
11. Fls gen present near base of st; pedicels near base of st stout, recurved; sepal midvein thickened-decurrent; st +/- prostrate .............................................................................................................................................................................................. P. scriptus
11' Fls gen not present near base of st; pedicels gen not stout, not recurved; sepal midvein not thickened-decurrent; st prostrate to erect
12. Attachment scar deeply concave
13. Nutlet dorsal surface rarely minutely bristled, but without large prickles or barb-tipped projections ........... P. trachycarpus
13' Nutlet dorsal surface with large prickles or protuberances barb-tipped or not, or rarely +- 0 .................... P. acanthocarpus
12' Attachment scar gen. not or only slightly concave
14. Nutlet attachment scar +- linear, slit- or keel-like near base .............................................................................. P. undulatus
14' Nutlet attachment scar narrowly elliptic to oblong, not linear, not slit- or keel-like
15. Nutlet attachment scar not oblique, parallelt to nutlet axis; nutlet surface minutely bristled or scabrous ... P. hispidulus
15' Nutlet attachment scar gen oblique; nutlet surface not bristly or scabrous
16. Nutlet ventral keel in a distinct trough ..................................................................... P. reticulatus var. rossianorum
16' Nutlet ventral keel not in a trough ......................................................................................................... P. bracteatus