Transcript ANGIOSPERM FAMILIES 03

ANGIOSPERM FAMILIES 03
ULMACEAE
THE ELM FAMILY
ULMACEAE
• Trees and shrubs.
• Widely distributed in the temperate regions of
both hemispheres, with a few species in the
tropics.
• 18 genera and about 150 species.
• Four genera in N America but only 2 are trees.
– Ulmus - elms
– Celtis - hackberries
CHARACTERISTICS OF THE FAMILY
• HABIT: trees or shrubs.
• LEAVES: alternate, simple, doubly serrate,
short-petioled, uneven base, distichous (in
one plane).
• VENATION: pinnate and netted.
• FRUIT: samara, drupe or nut.
DETAILS OF THE FLOWER
• Anemophilous
• Perfect
• Borne on slender pedicels in fascicles or
cymes.
• Ovary flattened
• Style 2-lobed
• Flowers appear before leaves in the spring;
some species flower in the summer or fall.
ULMUS AMERICANA FLOWERS
FLOWERS PERFECT
ANTHERS
FRUIT - SAMARA
PISTIL
CHARACTERISTICS OF THE GENUS ULMUS
• LEAVES: oblong-obovate to elliptical; margin
coarsely doubly serrate; apex acuminate; base
conspicuously uneven; surface scabrous
above, usually pubescent below.
• FLOWER: in fascicles, on long pedicels;
appearing before leaves in the spring.
• FRUIT: oval to oblong obovate, deeply
notched at the end; margins ciliate; a samara.
CHARACTERISTICS OF THE GENUS cont.
• TWIGS: slender, zigzag (sympodial), brown,
glabrous or slightly pubescent; lateral buds
ovoid, acute but not sharp-pointed, slightly
pubescent; chestnut brown.
• Grows in forests, river bottoms, swamps,
disturbed fields.
ULMUS CRASSIFOLIA Nutt.
Cedar elm
FRUITS - SAMARAS
TWIG WITH CORKY
OUTGROWTHS
LEAF COMPARISON
ULMUS AMERICANA
ULMUS CRASSIFOLIA
RANGE OF ULMUS AMERICANA
CHARACTERISTICS OF THE GENUS CELTIS L.
• LEAVES: deciduous, alternate, distichous,
single, simply serrate sometimes entire, base
unevenly cuneate.
• FLOWERS: perfect and imperfect (male,
female and hermaphrodite flowers on the
same plant – polygamo-monoecious);
staminate flower flower borne below in
fascicles; pistillate and perfect flowers above,
singly in the leaf axils.
CHARACTERISTICS OF THE GENUS cont.
• FRUIT: thick-skinned, thin-fleshed, ovoid or
globose drupe; pit surface with a reticulate
pattern.
• TWIGS: slender, zigzag; pith terete, very finely
chambered at the nodes, homogenous
elsewhere; terminal buds lacking; lateral buds
small, adpressed.
• LEAF SCARS: 2-ranked, oval to crescent;
bundle scars 3.
CELTIS LAEVIGATA WILLD.
Sugarberry
LEAF
TWIG - SYMPODIAL
BARK AND FRUITS OF CELTIS sp.
BARK OF C. OCCIDENTALIS
FRUIT OF C. LAEVIGATA
ZELKOVA SERRATA, an ornamental elm
from Japan, Taiwan and China
ECONOMIC IMPORTANCE OF THE
ULMACEAE
• Wood has commercial value.
• Valuable ornamental trees used in parks and
avenues.
• The fruit of elms and hackberries are an
important food source for wildlife.
• Elms are susceptible to the Dutch Elm Disease.