Key to Antirrhinum

View taxon page for Antirrhinum

(For a list of species in Antirrhinum, use the above link.)

Jepson Manual glossary definitions can be seen by moving your cursor over words underlined with dots.

1. Stamens 2, staminodes 2

2. Corolla 25–35 mm, white or cream to pale yellow ..... A. confertiflorum

2' Corolla 15–20 mm, bright yellow ..... A. mohavea

1' Stamens 4, staminodes 0

3. Pedicels 3–10 cm, twining or with U-shaped hook

4. Corolla of opening flowers yellow and gold with maroon flecks on lower lip; fruit fragile, opening by irregular bursting on sides ..... A. filipes

4' Corolla of opening flowers lavender to deep blue-purple, veins darker; fruit firm, 

dehiscent 

Opening at maturity to release contents; usually pertaining to anthers or fruits.

by 2 slits at tip ..... A. kelloggii

3' Pedicels 0.1–2.5 cm, not twining, not hooked

5. Proximal-most flowers not subtended by branchlets; flowers all opening; annual to 

perennial 

Completing life cycle (germination through death) in more than two years or growing seasons, generally non-woody (at least above ground) to woody; includes perennial herbs as well as subshrubs to trees; the abbreviation 'per' only refers to perennial herb, not to the word 'perennial' alone.

 herb; plants self-supporting

6. Lower calyx 

lobes 

1. A major expansion or bulge, such as on the margin of a leaf, sepal, or petal, or on the surface of an ovary. 2. The free tips of otherwise fused structures, such as sepals or petals; larger than teeth.

>= corolla tube; seed generally smooth, 1 side flattened, with raised, rough, irregular border ..... [A. orontium]

6' Lower calyx lobes < to << corolla tube; seed netted, ridged, or winged

7. Corolla 25–45 mm ..... [A. majus]

7' Corolla 7–18 mm

8. Flowers in terminal racemes; corolla 13–18 mm, pale pink to red; often perennial herb from 

caudex 

Generally short, sometimes woody, more or less vertical stem of a perennial, at or beneath ground level.

9. Plant sticky-glandular-hairy ..... A. thompsonii

9' Plant glabrous ..... A. virga

8' Flowers 1 in 

leaf 

Organ arising from a stem, generally composed of a stalk (petiole) and a flat, expanded, green, photosynthetic area (blade); distinguished from a leaflet by the presence in its axil of a bud, branch, thorn, or flower; sometimes with lateral, basal appendages (stipules); either simple (toothed, lobed, or dissected but not divided into leaflets) or compound (divided into leaflets).

 axils; corolla generally white, cream, or pale lavender, often with violet or purple veins or marks, 7–14 mm; annual

10. Corolla veins violet; swollen lower lip base with dense, 

cylindric 

Elongate, with parallel sides and, at any point, round in transverse section.

 hairs to 1 mm; KR, NCoRI, w CaR, n ScV ..... A. cornutum

10' Corolla veins not contrasting in color; swollen lower lip base with sparse, sphere-tipped hairs; SN (especially SNF) ..... A. leptaleum

5' Proximal-most flowers and often others generally subtended by branchlets; flowers all opening or some cleistogamous; annual, rarely biennial; plants often not self-supporting, but climbing or sprawling

11. Calyx lobes ± equal

12. Only stem base and inflorescence hairy; upper fruit chamber 

indehiscent 

Not opening inherently to release contents; usually pertaining to fruits.

..... A. coulterianum

12' Plant hairy throughout; both fruit chambers dehiscent ..... A. nuttallianum

13. Hairs very dense, very fine, of mixed lengths, tips ± not enlarged ..... subsp. nuttallianum

13' Hairs sparse to moderately dense, coarse, of ± = length, tips much-enlarged ..... subsp. subsessile

11' Calyx lobes unequal

14. Flowers cleistogamous and opening; corolla of opening flowers 5–7 mm, white, veins violet ..... A. kingii

14' Flowers all opening; corolla 8–20 mm, white to tan, cream tinged pink, or lavender

15. Corolla lower lip base not swollen, not closing throat, throat floor with 2 longitudinal folds ..... A. ovatum

15' Corolla lower lip base swollen, closing throat, throat floor without folds

16. Corolla white to tan, throat floor expanded at mouth, lower lip lobes 

reflexed 

Abruptly bent or curved downward or backward.

, poorly developed ..... A. subcordatum

16' Corolla lavender, throat uniformly narrowed, lower lip lobes thrust forward, 

erect 

Upright; vertically oriented.

or 

spreading 

Oriented more or less perpendicularly to the axis of attachment; often, more or less horizontal.

, conspicuous ..... A. vexillocalyculatum

17. Proximal stem glabrous or with nonglandular hairs to 3 mm; corolla 11–17 mm – s NCoR, ScV (Sutter Buttes), SnFrB, n SCoRI ..... subsp. vexillocalyculatum

17' Proximal stem glandular-hairy, with or without nonglandular hairs; corolla 8–14 mm

18. Branchlets subtending flowers with 1 leaf at proximal-most 

node 

Position on a stem from which one or more structures (especially leaves, buds, branches, or flowers) arise.

; KR, NCoR, CaRF ..... subsp. breweri

18' Branchlets subtending flowers generally with 2 leaves at proximal-most node; n&c SN ..... subsp. intermedium

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