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Pennellia tricornuta (Rollins) R.A. Price, C.D. Bailey & Al-Shehbaz (redirected from: Arabis tricornuta)
Family: Brassicaceae
Rincon Mountain rockcress
[Arabis tricornuta Rollins]
Pennellia tricornuta image
Jim Malusa  
Stems simple or few from base, 1.5-9 dm, pubescent proximally, trichomes simple and long-stalked, 2-3-rayed. Basal leaves usually persistent; petiole 0.5-3 cm; blade oblanceolate, 3-9 cm × 3-23 mm, margins dentate, surfaces pubescent, trichomes stalked, 2-4-rayed. Cauline leaves (distal) sessile; blade linear, 2.7-7.5 cm × 1-9 mm, surfaces glabrous or sparsely pubescent. Racemes secund, 2-6 dm in fruit. Fruiting pedicels ascending, arcuate, 7-11 mm. Flowers: sepals purple or green, oblong, 2.3-4 × 0.8-2.1 mm, (subequal); petals lavender apically, spatulate, (2.7-)3.3-4.5 × (0.5-) 1-1.5(-1.7) mm, (equal); filaments (1.7-)2-2.8(-3.3) mm; anthers 0.9-1(-1.3) mm. Fruits divaricate-ascending, straight or curved, 3.3-6.5 cm × 2-2.5 mm, latiseptate; valves glabrous; septum opaque; ovules 40-50 per ovary; style obsolete to 0.2 mm. Seeds uniseriate, flattened, winged, oblong, 2.4-2.8 × 1.2-1.9 mm; seed coat not mucilaginous when wetted; cotyledons accumbent. Flowering Jul-Sep. Steep rocky slopes, under pines, road and sand banks; of conservation concern; 1300-2800 m; Ariz. Pennellia tricornuta is known from Cochise, Pima, and Santa Cruz counties. It was recognized by R. C. Rollins (1941, 1993) under Arabis, but as shown by Price, Bailey & Al-Shehbaz and by S. Fuentes-Soriano (2004), it clearly belongs to Pennellia.

FNA 2010
Duration: Perennial Nativity: Native Lifeform: Forb/Herb General: Small herbaceous shrub with few individual stems, pubescent with long trichomes. Leaves: Oblanceolate basal leaves with dentate margins, pubescent, cauline leaves sessile with linear blades to 7.5 cm, pubescent or glabrous. Flowers: Light cream to purple, small and bell shaped, contracted at the tips, with purple to green sepals. Fruits: Ascending, divaricate, capsules, can be straight or curved, to 6.5 cm long, with broad partitions within, 40-50 ovules. Seeds flattened, oblong, and winged, not mucilaginous when wetted. Ecology: Found in dry areas on steep rocky slopes, roadsides, and in pine woods, from 4,500-9,000 ft (1372-2743 m); flowering July-September. Notes: FNA notes that this species is of conservation concern and is present in Cochise, Pima, and Santa Cruz counties. Ethnobotany: Unknown Etymology: Unknown Synonyms: Arabis tricornuta Editor: LCrumbacher, 2011
Pennellia tricornuta image
Dan Beckman  
Pennellia tricornuta image
Dan Beckman  
Pennellia tricornuta image
Dan Beckman  
Pennellia tricornuta image
Dan Beckman  
Pennellia tricornuta image
Dan Beckman  
Pennellia tricornuta image
Pennellia tricornuta image
Pennellia tricornuta image
Pennellia tricornuta image
Pennellia tricornuta image
Pennellia tricornuta image
Pennellia tricornuta image
Pennellia tricornuta image
Pennellia tricornuta image