''Planera'' is a
genus of
flowering plants with a single species, ''Planera aquatica'',
the planertree
or water elm. Found in the southeastern
United States, it is a small
deciduous tree 10–15 m tall, closely related to the
elms but with a softly, prickly
nut
Nut often refers to:
* Nut (fruit), fruit composed of a hard shell and a seed, or a collective noun for dry and edible fruits or seeds
* Nut (hardware), fastener used with a bolt
Nut or Nuts may also refer to:
Arts, entertainment, and media Com ...
10–15 mm diameter, instead of a winged seed. It grows, as the name suggests, on wet sites. Despite its common English name, this species is not a true elm, although it is a close relative of the elms (species of the genus ''Ulmus''). It is also subject to
Dutch elm disease, a disease which affects only members of the Ulmaceae. It is native to most of the southeast United States. It is hardy down to Zone 7.
Water Elm
Description
File:Water Elm, Planera aquatica, Bark.jpg, Bark
File:Planera aquatica, Water Elm, Leaves.jpg, Leaves
File:Planera aquatica, Water Elm. Underside of leaf.jpg, Leaf underside displaying pubescence
File:Water Elm, Planera aquatica, fruit.jpg, Fruit with and without shell
*
Leaves
A leaf (plural, : leaves) is any of the principal appendages of a vascular plant plant stem, stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", wh ...
: alternate, 3–7 cm long, with irregularly serrated to double serrated margins. Leaf base wedge-shaped or rounded. Leaf base often equal and symmetrical, but can be asymmetrical.
Thin
pubescent hair is often present on underside of leaf.
* Bark: gray-brown, thin, some flaky loose scales. Exfoliates to reveal red-brown area under bark.
* Fruit: a
drupe
In botany, a drupe (or stone fruit) is an indehiscent fruit in which an outer fleshy part (exocarp, or skin, and mesocarp, or flesh) surrounds a single shell (the ''pit'', ''stone'', or '' pyrena'') of hardened endocarp with a seed (''kernel'') ...
. Has a green shell that turns brown with age. Matures April - May.
Distinguishing Characteristics
While often confused with true elms, it can be easily distinguished by noticing the fruit are drupes and not
samaras. When fruit are not in season, the flaky bark is unique to water elm and not characteristic of true elms.
May also be confused with ''
Celtis'' (hackberries), but hackberry leaves have pronounced lower lateral veins not found on water elm.
Ecology
Typically found on alluvial floodplains subjected to seasonal or temporary flooding.
Often found in swamps, streams, lakes, or in riparian areas. Has some wildlife value, food for bees and some bird species. Prefers sandy or gravelly, moist soils.
Classified as an
obligate wetland plant (OBL).
References
Ulmaceae
Monotypic Rosales genera
Taxa named by Johann Friedrich Gmelin
{{Ulmaceae-stub