Convolvulaceae: Morning-glory Family — Calystegia & Convolvulus

Morning-glory is immediately recognizable, with its flaring white, pink or pink-striped funnel-shaped flowers.  Distinguishing individual species or subspecies is tricky.  You need to look at the bracts subtending the flower; these vary significantly in shape, position and hairiness.  Also, look closely at the shape of the leaves.  Finally, note the degree of hairiness and the shape of the “sinus”—the angle formed by the lobes at the base of the leaves.

Hillside Morning-glory – Calystegia collina subsp. collina

Blooms:

Apr–June

Plant Height:

Stem 8–15 cm

Flower Size:

Large

Origin:

Native

Habitat:

Open grassy or rocky places, open woodland, serpentine

Notes:

This can be difficult to distinguish from Hill Morning-glory (Calystegia subacaulis, see below).  Both of them have very short peduncles (< 6 cm), and both have  stems that are decumbent to ascending.  However, this one is clearly tomentose, and its leaves are kidney-shaped to triangular, with indistinct lobes and wavy margins.  The bracts are widely ovate, often hiding the calyx.

South Coast Range Morning-glory – Calystegia collina subsp. venusta

Blooms:

Apr–June

Plant Height:

Stem < 30 cm

Flower Size:

Large

Origin:

Native

Rare or Endangered?

Yes – 4.3

Habitat:

Rocky or gravelly places, often on serpentine

 

Notes:

Very similar to Hillside Morning-glory (subsp. collina, see above), but with some subtle differences.  This plant is found only in the extreme south or south-east of the county.  It is spreading-hairy to clearly tomentose, with creeping stems, 8–30 cm long (twice as long as the stems on Hillside Morning-glory).  The bracts completely cover the calyx; sepal lobes are tomentose.  Leaves are triangular to kidney-shaped, sometimes with indistinct lobes.  Be careful not to confuse this plant with the similar-named South Coast Morning-glory (Calystegia macrostegia subsp. intermedia), see below.

Coast Morning-glory – Calystegia macrostegia susbsp. cyclostegia

Blooms:

Mar–Aug

Plant Height:

Stem up to 2.5 m long

Flower Size:

Large

Origin:

Native

Habitat:

Coastal

Notes:

By far the most common morning-glory found near the coast, this often grows aggressively in other plants.  It has beautiful flowers, white to pink, funnel-shaped, often pink-striped below.  Its most distinctive feature is how its calyx is enclosed (or closely subtended) by a pair of large, widely ovate to rounded, sepal-like bracts with notched or narrowly pointed tips.  Leaves are triangular, and the sinus is variable: acute, rounded or squarish.

South Coast Morning-glory – Calystegia macrostegia subsp. intermedia

Blooms:

Mar–Aug

Plant Height:

Stem up to 2.5 m long

Flower Size:

Large

Origin:

Native

Habitat:

Coastal or inland hills

Notes:

This is similar to Coast Morning-glory (subsp. cyclostegia, see above), but distinguished by its bracts, which are lanceolate with acute tips.  Leaf lobes are rounded to 2-angled with the sinus either acute, rounded or squarish.  Common in southern California, and occasionally found in Monterey County.  Be careful not to confuse this plant with the similar-named South Coast Range Morning-glory (Calystegia collina subsp. venusta), see above.

Woolly Morning-glory – Calystegia malacophylla subsp. pedicillata

Blooms:

Mar–Aug

Plant Height:

Stem up to 1 m long

Flower Size:

Large

Origin:

Native

Habitat:

Mainly inland, rocky places above 300 m

Notes:

Like Hillside and South Coast Range Morning-glories (Calystegia collina, see above), this is tomentose.  But, unlike them, it has well-developed stems and its leaves are not noticeably wavy-edged.  The leaves themselves are gray-green, narrowly triangular in shape, with acute tips and single lobes.  The bracts are ovate, more or less hiding the calyx.

Purple-striped Morning-glory / Pacific false bindweed – Calystegia purpurata subsp. purpurata

Blooms:

May–July

Plant Height:

Stem up to 1 m long

Flower Size:

Large

Origin:

Native

Habitat:

Dry slopes away from immediate coast

Notes:

This is the most common morning-glory found on the Monterey Peninsula, away from the immediate coast.  It can be identified most easily by its 1–2 linear bract(s) which are a little below the calyx, occasionally overlapping but never covering it.  It has long peduncles, longer than the leaves.  The sinuses are a deep V-shape and sometimes even closed.

Beach Morning-glory – Calystegia soldanella

Blooms:

Apr–Aug

Plant Height:

Stem up to 60 cm long

Flower Size:

Large

Origin:

Native

Habitat:

Coastal strand

Notes:

This Morning-glory is one of the few that is easy to recognize, partly from its location and partly from its distinctive, fleshy, kidney-shaped leaves, broader than they are long.  The flowers are more rose to rose-purple than white.  The bracts more or less cover the calyx and are obtuse or notched at the tip.  Photo #3 by CJH.

Morning-glory, Beach

Hill / Stemless Morning-glory – Calystegia subacaulis subsp. subacaulis

Blooms:

Apr–June

Plant Height:

Stem +/- 2 cm

Flower Size:

Large

Origin:

Native

Habitat:

Open grassy slopes, mainly inland

Notes:

“Stemless” is an exaggeration, but the stem is very short, only about half the length of Hillside Morning-glory (Calystegia collina subsp. collina, see above), with which this species can easily be confused.  Both plants have stems that are decumbent to ascending.  Leaves are variable, more or less triangular-hastate, sometimes with 2 backward pointing lobes, a tapered base and with an acute or rounded tip.  Leaf margins may be either flat or wavy.  The plant can be hairy, but is not tomentose like Hillside Morning-glory.  The flower is subtended by bracts, which are narrow and equal in length to the calyx, but do not conceal it.

Field Bindweed – Convolvulus arvensis

Blooms:

Mar–Oct

Plant Height:

Vine-like

Flower Size:

Large

Origin:

Europe

Habitat:

Roadsides and open areas in many communities

Notes:

The only non-native among the Morning-glories found in the county.  It has white to pink-tinged flowers, pink-striped below.  Its leaves are arrow-shaped with generally rounded tips.  The slender bracts (linear to oblanceolate) are on the stem well below the flower.  The stigma is linear to spoon-shaped and cleft. This plant is widely loathed by gardeners in its native Europe since its spreads aggressively, has deep roots and is almost impossible to eradicate.