Fabaceae: Pea Family — Annual Lupines

The pea family has 5-petaled flowers, consisting of a wide upper banner petal, two wing petals, plus two lower petals which are fused to form a boat-shaped keel.  Many genera have flowers in heads or spikes, comprising many individual flowers.  Examples are lupines and clovers.  The seed pod is generally a “legume”.  This is a long, flattish pod, swollen by the seeds, and splitting lengthwise along both the top and bottom.

Most lupines are easily recognized as such with their distinct clusters of flowers in spikes, sometimes short, sometimes quite tall.  Leaves are typically palmately compound, with leaflets ranging from the very narrow to the comparatively broad.  If in doubt, it is useful to note whether the flowers are in whorls around the stem.  It can also be critical to look at the keel, to see the pattern of hairs.   Some are ciliate on both the top and bottom of the keel; some have hairs only near the claw (base), others only near the tip.  Photographs of some keels appear below.

Spider Lupine / Bentham’s Annual Lupine  – Lupinus benthamii

Blooms:

Mar–May

Plant Height:

20–70 cm

Flower Size:

Large cluster

Origin:

Native

Habitat:

Rocky slopes, open areas, outer coast ranges

Notes:

Found only in the southern parts of the outer coast ranges.  This is common along the Nacimiento-Fergusson Road, just west of Fort Hunter Liggett.  It looks at first sight like a bush lupine, but is in fact an annual.  It is easily identified by its tall clusters of bluish-purple flowers and the very slender, thread-like leaflets that give the plant its common name.  Flowers may be whorled.  Keels are ciliate along the lower margin near the claw.

Miniature Lupine / Lindley’s Annual Lupine  – Lupinus bicolor

Blooms:

Mar–June

Plant Height:

10–40 cm

Flower Size:

Medium cluster

Origin:

Native

Habitat:

Heavy soils, many communities

Notes:

A low, fairly inconspicuous plant, often growing with and sometimes confused with immature Sky Lupine (Lupinus nanus, see below).  The flower clusters are smaller, and the white banner spot on the keel is taller than it is wide (the opposite of Sky Lupine), and wraps around less deeply.  Flowers are whorled with shorter pedicels toward the top.  The keel is generally ciliate on the upper margin near the pointed tip.  Miniature Lupine can also be confused with the much less common Big Pod Lupine (Lupinus pachylobus, see below), but the size of the fruits and seeds of the latter allow them to be distinguished without too much difficulty.

Bajada Lupine  – Lupinus concinnus

Blooms:

Mar–May

Plant Height:

10–30 cm

Flower Size:

Medium cluster

Origin:

Native

Habitat:

Dry open disturbed places

Notes:

A small plant with decumbent to erect stems, it is notable for the long, spreading hairs covering its stem and leaves.  Leaves have 5–9 leaflets, 1-3 cm long.  The inflorescence is a dense spiral, up to 9 cm tall, of pink to purple (occasionally white) flowers.  Some of the flowers appear on lower leaf axils.  The banner spot is white or yellowish.  The keel is generally glabrous.

Stinging Lupine  – Lupinus hirsutissimus

Blooms:

Mar–May

Plant Height:

20–80 cm

Flower Size:

Large cluster

Origin:

Native

Habitat:

Open sunny, often disturbed places

Notes:

This is one of the more easily recognized lupines.  It has bright pink to magenta flowers, a very hairy stem, hairy leaves with a bumpy or blistered appearance, divided into 5–8 broad leaflets.  The stems and leaf hairs can deliver an unpleasant sting, so the plant is best handled with care.  The flowers are not whorled, growing on either side of the stem on short pedicels.  The keel is ciliate on the lower margin, between the middle and the claw.

Chick Lupine  – Lupinus microcarpus var. densiflorus

Blooms:

Apr–June

Plant Height:

10–80 cm

Flower Size:

Large cluster

Origin:

Native

Habitat:

Clay soils, common on roadsides

Notes:

This is California’s only lupine with white or cream-colored flowers.  Some flowers may turn pink with age.   Both calyx and bracts have sparse, appressed to spreading hairs.  Fruits are concentrated on one side of the stem.  The keel is ciliate on the upper margin, near the claw.

Chick / Valley Lupine  – Lupinus microcarpus var. microcarpus

Blooms:

Mar–June

Plant Height:

10–80 cm

Flower Size:

Large cluster

Origin:

Native

Habitat:

Clay soils, dry places

Notes:

Although the same genus as Chick Lupine (var. densiflorus, see above), this has several material differences.  First the color of the flowers is typically pink to purple.  Second, the fruits are not concentrated on one side of the stem.   Third, both calyx and bracts have denser, long shaggy hairs.

Sky Lupine  – Lupinus nanus

Blooms:

Mar–June

Plant Height:

10–60 cm

Flower Size:

Large cluster

Origin:

Native

Habitat:

Open or disturbed areas

Notes:

The most common of the lupines in the Outer Coast Ranges, sometimes found in great profusion.  The flowers are blue-purple with a purple-dotted, narrow white banner spot.  As with other lupines, the spot turns reddish or violet after pollination.  The keel is ciliate on the upper margin near the tip.

Big Pod Lupine  – Lupinus pachylobus

Blooms:

Mar–May

Plant Height:

15–40 cm

Flower Size:

Small cluster

Origin:

Native

Habitat:

Grassy slopes

Notes:

Similar to Miniature Lupine (Lupinus bicolor, see above), this can be distinguished by its fruits.  They are densely hairy, and large, 3 cm long and 6–9 mm wide (as against 1–3 cm long and 3–6 mm wide for Miniature Lupine).  Seeds also are larger, 4–5 mm long (twice the size of the Miniature Lupine’s seeds).  The keel is blunt and glabrous.

Harlequin Lupine  – Lupinus stiversii

Blooms:

Apr–June

Plant Height:

10–50 cm

Flower Size:

Medium cluster

Origin:

Native

Habitat:

Above 550 m in gravelly or sandy areas

Notes:

Uncommon but unmistakable.  It has a 3–8 cm tall, multi-colored inflorescence with a yellow banner, rose to purple wings and whitish keel.  The keel is ciliate on both margins, from the middle to the claw.

Arroyo Lupine  – Lupinus succulentus

Blooms:

Feb–May

Plant Height:

20–100 cm

Flower Size:

Large cluster

Origin:

Native

Habitat:

Grassy flats & slopes

Notes:

Like Broad-leaved Lupine (Lupinus latifolius), this has broad leaves, but leaflets are fewer (6–9) and smaller (2–6 cm).  In addition, it is a smaller plant, and its inflorescence is both shorter (< 15 cm), much deeper purple and less open.  The banner is yellowish-white, turning magenta after pollination.  The keel is ciliate on both margins near the claw.

Nuttall’s Annual Lupine  – Lupinus truncatus

Blooms:

Mar–May

Plant Height:

20–30(50) cm

Flower Size:

Large cluster

Origin:

Native

Habitat:

Openings in chaparral and woodland

Notes:

A fairly common and distinctive lupine with its slender, very open inflorescence.  It has magenta to dark purple flowers, and its narrow leaflets have more or less squared-off ends.