sandyseed clammyweed

(Polanisia dodecandra ssp. trachysperma)

               
Conservation Status

IUCN Red List

not yet assessed

 

No image available

NatureServe

NNR - Unranked

SNR - Unranked

Minnesota

not listed

Wetland
Indicator
Status

Great Plains

FACU - Facultative upland

Midwest

UPL - Obligate upland

Northcentral & Northeast

UPL - Obligate upland

Nativity

Native

 
Occurrence

 

 
Habitat

Moderately moist to dry. River banks, streamsides, roadsides, railroads, and other disturbed sites. Gravelly or sandy soil. Full sun.

 
Flowering

July to September

 
Flower Color

White

 
Height

12 to 24

 

Identification

This is an erect, annual, 4 to 15¾ tall forb that rises usually on a single stem from a taproot.

The stem is round, green to reddish-purple, sparsely to moderately branched, and covered with two types of hairs. It is densely covered with minute, spreading, gland-tipped hairs, and moderately to densely covered with longer, matted hairs that are often also gland-tipped. It is sticky to the touch and has a disagreeable odor when crushed.

The leaves are alternate. Lower and middle leaves are on 13 16 to 2 long leaf stalks (petioles) and are divided into three leaflets (ternately compound). Upper leaves are undivided and are on shorter stalks or are nearly stalkless. The petioles are green to purple and are densely covered with gland-tipped hairs. At the base of each petiole there is an inconspicuous, hair-like, less than 1 32 long appendage (stipule). The stipules whither quickly and may not be visible except on very young leaves.

The leaflets are narrowly egg-shaped or inversely lance-shaped, ¾ to 2 long, and 5 16 to 13 16 wide. They are narrowed or tapered at the base and usually bluntly pointed, sometimes sharply pointed, at the tip. The upper and lower surfaces are covered with gland-tipped hairs. The margins are untoothed.

The inflorescence is an unbranched, flat-topped, usually dense cluster (raceme) of many flowers at the end of each stem. The raceme on the central stem can be up to 8 long, one-half the length of the stem. Racemes on side stems are shorter. The flowers are on green to purple, to 1 long stalks (pedicels). Each pedicel is subtended by a lance-shaped to egg-shaped, 5 16 to long, 1 16to 3 16 wide modified leaf (bract).

Each flower is about ½ long and bilaterally symmetrical, having only one plane of symmetry. There are 4 sepals, 4 petals, 12 to 18 stamens, and 1 style. The sepals are purple, oblong, to ¼ long, 1 32 to 1 16 wide, and fused at the base. The petals are white. They are spatula-shaped, 5 16 to ½ long, to 3 16 wide, and narrowed to a stalk-like, to 3 16 long base. The upper pair of petals are longer than the lower pair. The upper pair and usually the lower pair are shallowly and broadly notched at the tip. The stamens have purple, to ¾ long stalks (filaments) and purple, 1 32 to 1 16long anthers. They are unequal in size because they mature at different rates. At maturity, they are about twice as long as the upper petals. They wither away after fertilization. The pistil is borne on a short, 1 16to 5 16 long, stalk-like extension (gynophore) of the the receptacle. The gynophore does not elongate as the fruit matures. The style is 3 16 to long. The stigma is purple.

The flowers bloom from the bottom up. The raceme continues to elongate as fruits develop, eventually becoming 4 to 11 ¾ long. The fruit is a pea-like, oblong, slender, cylinder-shaped, 1½ to 2 long, 3 16 to 7 16 wide capsule with 20 to 65 seeds. The capsule is green at first, turning brown as it matures. It is inflated and densely covered with sticky glandular hairs. It is held erect or strongly ascending. The style drops off as the fruit forms.

 
Similar
Species

Redwhisker clammyweed (Polanisia dodecandra ssp. dodecandra) is a smaller plant, 4 to 16 tall. The leaves are smaller and on much shorter petioles. The flowers are smaller and have fewer stamens. Mature stamens are only slightly longer than the upper petals. The fruits are slightly smaller. It is the eastern subspecies and is found throughout the state.


Distribution Distribution Map  

Sources: 3, 4, 28, 29, 30.


Comments

What’s in a Name?
The stem, foliage, and fruit are covered with sticky glandular hairs. Touching them leaves the fingers feeling “clammy”.


Taxonomy

Family:

Cleomaceae (cleome)

 
Parent

roughseed clammyweed (Polanisia dodecandra)

 
Synonyms

Polanisia dodecandra var. trachysperma

Polanisia trachysperma

 
Common
Names

clammyweed

large-flowered clammyweed

red-whisker clammyweed

sandyseed clammyweed

western clammyweed

   

 

 

 

 

 

 

 

 

 

Glossary

Bract

Modified leaf at the base of a flower stalk or flower cluster.

 

Gynophore

A long or short, stalk-like extension of the receptacle on some flowers on which the pistil is borne.

 

Pedicel

In plants: the stalk of a single flower in a cluster of flowers. In Hymenoptera and Araneae: the narrow stalk connecting the thorax to the abdomen.

 

Petiole

The stalk of a leaf blade or compound leaf that attaches the leaf blade to the stem.

 

Raceme

An unbranched, elongated inflorescence with stalked flowers. The flowers mature from the bottom up.

 

Receptacle

The thickened, upper part of a flower stalk to which flowers or flower parts are attached. In composite flowers, the part on which the florets are borne. In accessory fruits the receptacle gives rise to the edible part of the fruit.

 

Stipule

A small, leaf-like, scale-like, glandular, or rarely spiny appendage found at the base of a leaf stalk, usually occurring in pairs and usually dropping soon.

 

Ternate

Refers to leaves that are divided into three leaflets or sections.

       

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