Shinnersia

Scientific name

Shinnersia R.M. King & H. Rob.

Common names

Mexican oakleaf

Family

Asteraceae

Similar genera

Hygrophila, Penthorum, Myosotis

Native distribution

Mexico

Species cultivated

Shinnersia rivularis (A. Gray) R.M. King & H. Rob.

Adventive distribution

information not available

Weed status

not weedy

Habit

submersed, creeping to emergentemergent:
(adj) (syn. emersed) with parts raised out of the water; extending up out of the water
stem plant

Brief description

Annual or perennialperennial:
(adj) (of a plant) having a life cycle of more than two years
. Stems creeping or ascending, branching regularly. Leaves oppositeopposite:
(adj) (of leaves) two leaves per node; in pairs on opposite sides of an axis
, decussatedecussate:
(adj) arranged along stem in pairs, with each pair at right angles to the pairs above and below
, sessilesessile:
(adj) attached directly, without a stalk
, oblanceolateoblanceolate:
(adj) lance-shaped, with attachment at or near the narrow end. (compare lanceolate)
, entireentire:
(adj) having a continuous margin that is not toothed or lobed
or with 3- to 5-lobed lacerations. Inflorescenceinflorescence:
(n) the arrangement of flowers on the floral axis
terminal, a hemispherical headhead:
(n) inflorescence consisting of small closely packed stalkless flowers or florets arising at the same level on a flattened axis; of several types, including: discoid (composed entirely of disk flowers) and radiate (composed of central disk flowers and marginal ray flowers)
, solitary or rarely paired; pedunclepeduncle:
(n) the stalk of a flower cluster or inflorescence
up to +/- 8 cm long; florets 90-100 per headhead:
(n) inflorescence consisting of small closely packed stalkless flowers or florets arising at the same level on a flattened axis; of several types, including: discoid (composed entirely of disk flowers) and radiate (composed of central disk flowers and marginal ray flowers)
. Calyxcalyx:
(n) the outer whorl of the perianth; all the sepals of a flower
lacking pappuspappus:
(n) modified calyx in the Asteraceae, composed of hairs, bristles, awns, or scales
; corollacorolla:
(n) the inner whorl(s) of the perianth; all the petals of a flower
tubular, 5-lobed, white. Dispersal by stem fragments or acheneachene:
(n) a dry, indehiscent, one-seeded fruit in which the seed is attached to the pericarp at a single point
.

Natural habitat

shallow water and wet ground

Additional comments

Originally placed in the genus Trichocoronis A. Gray, but separated based on floral characters into the monotypicmonotypic:
(adj) represented by a single example (species)
genus Shinnersia.