Rosids – Part 3:Eurosids I – Fagales; Myrtales

Spring 2010

“Lower”Core tricolpates

Rosids

(Eurosids II)

(Eurosids I)

“Basal” rosids

Figure 9.3 from the text

Core Eudicots: The Rosids Lecture 3“Basal” Rosids:

Order VitalesEurosids I (Fabids):

Order MalpighialesOrder CucurbitalesOrder FabalesOrder RosalesOrder Fagales

Fagaceae – Beeches, oaksBetulaceae – Birches Juglandaceae – Walnuts

Order MyrtalesOnagraceae – Evening primrosesMyrtaceae – Eucalypts, myrtles

Eurosids II (Malvids)

Eurosids I:Fagales: Fagaceae

(The Oak and Beech Family)

• Widespread, in tropical to temperate regions of the Northern Hemisphere

• Trees and shrubs• Diversity: 700 species in 8 genera• Flowers: Unisexual; Tepals usually 6 and reduced,

inconspicuous; stamens 4-many; carpels 3 (-12), connate, inferior ovary; fruit a nut, associated with a spiny or scaly cupule

• Significant features: Male inflorescences in dangling catkins; female inflorescences in sessile clusters

• Special uses: edible nuts (chestnuts), lumber, tannin, cork; ornamental trees

• Required taxa: Quercus, *Fagus *change from lab manual

Fagaceae: Quercus

• Bark pale to dark but scaly or furrowed• Buds clustered at twig tips, ovate• Leaves lobed or unlobed• Male flowers in drooping catkins• Cupule saucer-like or cup-shaped• Nut circular in cross-section

Fagaceae: Fagus

• Bark light gray, smooth• Buds solitary at twig tips, slender and

acute• Leaves unlobed, strongly straight-veined• Male flowers in a rounded head• Cupule with 4 valves• Nut compressed or triangular

Eurosids I:Fagales: Betulaceae

(The Birch Family)

• Widespread, in temperate to boreal regions, primarily of the northern hemisphere

• Trees or shrubs; leaves doubly serrate• Diversity: 110 species in 6 genera• Flowers: Unisexual; tepals (0-) 1-4 (-6), highly reduced;

stamens 1-4; carpels 2, connate, inferior ovary; fruit an achene, nut or 2-winged samara

• Significant features: Flowers in erect (female) or pendant (male) catkins (aments); staminate and carpellate flowers in separate inflorescences

• Special uses: hazel nuts edible; lumber, shade trees, ornamentals

• Required taxa: Betula

Betulaceae: Betula

• Outer bark often separating in thin sheets• Carpellate and staminate flowers both in

bracteate catkins • Carpellate catkins ovoid to cylindrical,

with 2-3 flowers per bract and the bracts papery

• Staminate flowers 3 per bract; stamens 2, bifid

Eurosids I:Fagales: Juglandaceae

(The Walnut and Hickory Family)• Widespread from tropical to temperate regions• Aromatic trees; leaves pinnately compound, usually

alternate and spiral• Diversity: 59 species in 8 genera• Flowers: Unisexual, associated with bracts; tepals 0-4,

inconspicuous; stamens 3-many; carpels usually 2, connate, ovary inferior; fruit a nut or nutlet

• Significant features: Fruit often associated with bracts or bracteoles that form an outer “husk”

• Special uses: fruits of hickories (Carya) and walnuts (Juglans) are eaten; walnut and hickory are valued for their lumber; some ornamentals

• Required taxa: Juglans, Carya

Juglandaceae: Juglans

• Twigs with chambered pith• Leaflets all about the same or the median

ones largest• Staminate catkins sessile, solitary• Nut with an indehiscent, usually rough or

furrowed husk

Juglandaceae: Carya

• Twigs with solid pith• Apical leaflets largest• Staminate catkins sessile or pedunculate,

in clusters• Nut with a dehiscent or partially dehiscent,

often smooth husk

Eurosids I:Myrtales: Onagraceae

(The Evening Primrose Family)

• Widely distributed, primarily in western North America and South America• Mostly herbs, some shrubs, trees • Diversity: 655 species in 18 genera• Flowers: Showy; sepals & petals (2-) 4 (-7);

stamens (4) 8, not incurved in bud, pollen with viscin threads; carpels usually 4; ovary inferior; long hypanthium; cruciform stigmas; fruit is a loculicidal capsule or berry• Significant features: Tetramerous flowers!!• Special uses: Several ornamental herbs • Required taxa: Oenothera

Onagraceae: Oenothera

• Herbaceous• Leaves usually alternate• Hypanthium prolonged beyond the ovary• Corolla usually yellow (can be white or

pink)• Fruit a loculicidal capsule with many

seeds or nut-like, indehiscent and few-seeded

• Seeds naked

Eurosids I:Myrtales: Myrtaceae(The Eucalyptus or Myrtle Family)

• Pantropical; highly diverse in warm temperate Australia• Trees or shrubs often with flaky bark• Diversity: 4,630 species in 144 genera• Flowers: Hypanthium well developed; sepals and petals 4-5;

stamens usually numerous; carpels 2-5, connate; ovary inferior to half-inferior; fruit usually a 1-many seeded berry or loculicidal capsule

• Significant features: Highly aromatic leaves & stems due to many terpenoid and resinous compounds; leaves entire with scattered pellucid dots containing these compounds

• Special uses: Eucalyptus important source of timber; many used as ornamentals; cloves (Syzygium aromaticum); guava (Psidium guajava)

• Required taxa: Eucalyptus

Myrtaceae: Eucalyptus• Foliage dimorphic (juvenile leaves are

rounded & stem-clasping; adult leaves are longer, willowy, and petioled)

• Flower buds covered by an operculum (fused sepals or petals or both) that falls off at anthesis

• Fruit a conical capsule (gumnut)• Primarily Australian; ca. 800 species, some cultivated in the U.S.