by Bob Harms 

Leaves of Berberis swaseyi

Key features

Ahrendt 1961

Leaves with only 2-4 pairs of leaflets; stamens dentate; style absent.

Leaves closely reticulate; bracts foliaceous, 3-9 mm. long; fruit yellowish red, epruinose, 10-12 mm. long.
... 604. M. swaseyi

Whittemore (FNA, Vol. 3)

7. (6) Leaves 5-11-foliolate (sometimes a minority of leaves 3-foliolate); terminal leaflet stalked on most or all leaves.

9(7). Marginal spines of leaflet blade 0.4-1.2 x 0.1-0.15 mm.

10 (9) Bracteoles (at least proximal ones) leathery, spine-tipped; berries white or red, somewhat glaucous, 9-16 mm, usually hollow; c Texas.
... 11 Berberis swaseyi

Correll & Johnston 1970

1. Leaves pinnately lobed; leaflets 5 or more (2)

2(1). Bracts of inflorescence foliaceous; fruits globose, about 12 mm. in diameter, grading in color from white to brilliant-red, shiny; in west-central Texas.
... 2. B. swaseyi.

Specific descriptions

Ahrendt 1961

• Leaves 5-9 x 4-6 cm., with (2-) 3 (-4) pairs of remote leaflets,
• the lowest pair shorter and broader, c. 3 x 1.75 cm., set only 1-2 mm. above the base of the rachis, the remaining internodes decreasing upwards from 15-20 to 10-12 mm.
  
• Leaflets moderately thick, 2.5-3.2 x 0.6-0.8 cm.;
  
• base sessile or with petiolule 1-2 mm. long;
  
• margins 4-6 spinose (1-1.5 mm.)-serrate (1-1.5 mm.), distant 3-6 mm.;
  
• above grey-green; below pruinose grey; both sides fairly closely reticulate.

Whittemore (FNA, Vol. 3)

• Leaves 5-9-foliolate (basal pair of leaflets sometimes reduced to bristles); petioles 0.1-0.5 cm.
• Leaflet blades thin or thick and rigid;
• surfaces abaxially dull, papillose, adaxially dull, somewhat glaucous;
• terminal leaflet stalked (sessile in a few leaves), blades 1.8-3.5 x 0.7-1.7 cm, 1.3-4.7 times as long as wide;
• lateral leaflets oblong to elliptic or lanceolate, 1-veined from base, base truncate to obtuse, rarely acute, margins plane or undulate, toothed, each with 3-8 teeth 0.5-2 mm high tipped with spines to 0.6-1.2 x 0.1-0.2 mm, apex rounded to acuminate.

Correll & Johnston 1970

• leaflets 5 to 9,
• thinly coriaceous, grayish green or yellowish-green on upper surface, paler and conspicuously venose on lower surface,
• elliptic to elliptic-lanceolate or subquadrate,
• the 7 to 20 spines relatively weak,
• turning a deep red in fall

Leaves of Berberis trifoliolata

Key features

Ahrendt 1961

Leaves with only one pair of leaflets; stamens edentate; fruit blue-black, style distinct.
... 602. M. trifoliolata

(602) Leaflets above slightly lustrous green, and epapillose
... 602a. M. trifoliolata var. trifoliolata

(602) Leaflets above conspicuously grey-green, and very minutely and closely papillose
... 602b. M. trifoliolata var. glauca

Whittemore (FNA, Vol. 3)

7.(6) All leaves 3-foliolate; terminal leaflet sessile.

8 (7) Terminal leaflet blade 0.9-2 cm wide; berries red.
... .... 6. Berberis trifoliolata

Correll & Johnston 1970

1. Leaves palmately trifoliate; leaflets sessile at apex of petiole
... 1. B. trifoliolata

Specific descriptions

Ahrendt 1961

• Leaves trifoliate, having but one pair of leaflets, set 1.5 cm. above the base.
• Leaflets fairly thick, 2-6 x 1-1.5 cm.; margins (1-) 2 (-3) spinose (1-2 mm.) - dentate (2.5-7 mm.), distant 1.5-2 cm.;
• terminal leaflet sessile;
• both sides subenervate.

Whittemore (FNA, Vol. 3)

• Leaves 3-foliolate; petioles 0.8-5.4 cm.
• Leaflet blades thick and rigid;
• surfaces abaxially dull, papillose, adaxially dull,