Download Lecture 7 (Word doc)

Rosid Clade, Part I
Saxifragales, Geraniales, Malpighiales, Fabales, Rosales
Saxifragaceae
Crassulaceae
Sedum laxum! (notice clonality)
Diverse habits:
Geraniaceae
Habit: Herbs to subshrubs; stems jointed at nodes.
Leaves: Variable – alternate-opposite, simple-lobed-dissectedcompound. Venation palmate.
Flowers: Bisexual (usually), hypogynous, radial or bilateral. Often
protandrous, but some highly selfing and weedy.
- Perianth: Sepals and petals – usually 5 of each.
- Androecium: Stamens usually 10-15, sometimes 5. Pollen grains
tricolporate.
- Gynoecium: Usually 5 connate carpels. Style 1, stigmas 5. Elongate,
persistent, terminal sterile column! (see image of seeds dehiscing).
Fruit: Schizocarp with 5 one-seeded segments around persistent
column. Read about these and their evolutionary innovations in Judd!
Pretty amazing dispersal mechanisms Outliers:
Gestalt: Palmate leaves, lobed to dissected; flower parts in 5s, one style
with 5 stigmas. Fruits elongate with beak.Hairs often gland-headed and
with ethereal oils.
Geraniaceae fruits – not quite mature on left, and dehiscing on right. Note that these seeds (5 per
flower) are one of the things that you are probably finding poling you in the field during lab, and
stuck to your clothing when you get home… very pointy, sharp seeds with a corkscrewed
attachment. Also notice, in the photo on the right, the persistent sterile column in the center of
these five seeds. You can easily find these in the field as well if you look - or ask Jer or I to find
one for you.
Violaceae
Habit: All in N. America are herbs.
Leaves: Simple, sometimes lobed. Margin entire to serrate.
Flowers: Usually bisexual, bilateral.
- Perianth: Sepals and petals – 5 of each. Abaxial (anterior)
petal sometimes spurred, and holding a nectar reward for
pollinators.
- Androecium: Usually of 5 stamens, filaments short and
anthers connate – forming a ring around the styles. This
connation of anthers is very noticeable if you tear a flower
off to look – do this!
- Gynoecium: Usually 3 connate carpels, ovary superior.
Style 1, often curved, hooked, or otherwise modified.
Stigma usually expanded.
Fruit: Usually a loculicidal capsule, seeds often arillate.
Outliers: Sometimes shrubs or small trees. Sometimes less
obviously bilateral flowers.
Gestalt: Bilateral flowers, simple leaves with palmate venation;
connate anthers on short filaments. Pretty easy to get a gestalt
for the flowers on these – perhaps you already have one?
Other cool stuff: Cleistogamous flowers! (see below)
Violaceae habit:
Cleistogamous flowers (Violaceae). Cleistogamous flowers are flowers that remain in bud
(never opening), and set seed via self-pollination. The photo above shows cleistogamous flowers
on a Viola; this is one of two genera in this family that has cleistogamous flowers.
Cleistogamous flowers are usually found near the base of the plant, hidden under leaves, but
sometimes these flowers are underground!
Fabaceae
Habit: Herbs, shrubs, vines, trees.
Leaves: Usually alternate; usually compound or twicecompound, sometimes trifoliate. Stipules inconspicuous to
leaflike.
Flowers: Usually bisexual, radial to bilateral*. (* subfamily
Mimosoideae has radial flowers; others are bilateral).
- Perianth: Sepals and petals, usually 5 of each. Sepals
usually connate; petals distinct or connate, forming banner
(1 petal), wings (one petal each, so 2 total for the wings)
and keel (2 fused petals). See photo below, and also
experiment with the lupines in the field.
- Androecium: Usually 10 stamens, hidden by perianth to
long-exserted; can be showy (Mimosa). Filaments distinct
to connate. Pollen grains vary (triocolpate, tricolporate,
triporate).
- Gynoecium: Usually 1 carpel; ovary superior; style and
stigma 1.
Fruit: Variable, but usually a legume.
Outliers: Spines (modified stipules, as with Acacia), sometimes
2-16 carpels; unifoliate; sometimes radial flowers /
inflorescences (as with Mimosa and Acacia, for example).
Gestalt: Compound leaves (and twice-compound), bilateral
flowers.
Other cool things: Notice the sleep behavior of the leaves –
leaves and leaflets fold along axes in the evening, or in some
(like the Mimosa on display in the lab) they will fold together
when touched.
There are 3 subfamilies of Fabaceae: I am not going to ask you to distinguish between these,
but I would like you to be able to recognize that a plant within any of these groups is in the
Fabaceae – Mimosoideae (includes Acacia and Mimosa)
– “Caesalpinioideae” (includes redbuds)
– Faboideae (includes peas, beans, and clovers)
Fabaceae: Mimosoideae
Mimosa sp. – notice twice-pinnately-compound leaves.
Inflorescence of Mimosa sp.: this is a dense head of flowers which open roughly simultaneously;
corollas are radial in symmetry, and individually not very showy. Stamens are the showy part of
these inflorescences.
Leaves usually twice-pinnately compound.
Mimosa sp. fruit – quite pea-like!
Fabaceae: "Caesalpinioideae"
Flowers usually bilateral, some radial. Leaves usually pinnately compound or twice-pinnately
compound.
Fabaceae: Papilionideae
Includes most peas, clovers, wisteria, lupines, Astragalus… notice the familiar habit below:
Focus below on the details of individual flowers: note the bilateral symmetry, as well as the
banner (composed of one petal, and serving as a visual attractant to pollinators), the wings (each
wing composed of one petal – there are two wings, so two wing-petals; sometimes these are
partially fused to each other), and the keel (tucked within the wings, and enclosing the stamens
and style – this is composed of two fused petals).
Rosaceae
Habit: Herbs, shrubs, or trees, sometimes with thorns.
Leaves: Usually alternate, simple to often palmately or
pinnately compound. Stipules usually present.
Flowers: Usually bisexual, and usually radial. Hypanthium
present, but variable in shape.
 Perianth: Of sepals and petals, usually 5 of each. petals
often clawed. Horticultural varieties with more than 5
petals!
 Androecium: Usually numerous stamens (15-∞), but
sometimes 10 or fewer. Pollen tricolporate.
 Gynoecium: 1-many carpels, distinct or connate. Ovary
superior – inferior; styles same in number as carpels.
Fruit: Variable! Note that many of our fruits (and nuts) are
from this family: apples, strawberry, peaches, blackberry,
almonds, etc…
Outliers: Flowers sometimes unisexual (plants monoecious or
dioecious). Flowers without corolla. Stamens not numerous.
Gestalt: Petals/sepals in 5s; numerous stamens. Look for a
hypanthium to distinguish from Ranunculaceae! Leaves are
quite variable in this family, but sometimes the presence of
stipules can help decide if a plant should be in Rosaceae (which
has stipules) or Saxifragaceae (which does not).
Rosaceae – notice hypanthium:
Ranunculaceae – no hypanthium:
Just to give you a sense of that this family can be highly variable in overall habit: this is an
Aruncus sp., also in Rosaceae:
Rhamnaceae
Habit: Trees, shrubs, sometimes with thorns.
Leaves: Alternate (occasionally opposite), simple, prominent
primary and secondary venation.
Flowers: Usually bisexual, small, with hypanthium. Radial.
 Perianth: Sepals and petals, usually 5 of each. Petals
usually clawed, concave and hooded – enclosing anther at
time of flowering. Petals often greenish. Nectariferous
disk surrounding the ovary!
 Androecium: Of 5 stamens, opposite petals. Filaments
adnate to base of petals.
 Gynoecium: Usually of 2-3 connate carpels; style 1;
stigmas capitate and equal in number to carpels. Ovary
superior to inferior.
Fruit: Dehiscent to indehiscent drupe.
Outliers: Sometimes flower parts in 4. Sometimes apetalous.l
Gestalt: Stamens opposite petals; flowers small and clustered in
axillary corymbs, with clawed petals. Primary and secondary
venation of leaves prominent. Nectariferous disk surrounding
the ovary.
Most common genus around here is Ceanothus:
Closer look at the flowers – notice the petals are hooded and enclosing the anthers.
And closer yet (now a different genus): Notice flowers with clawed petals, and nectariferous
disk surrounding ovary -
Leaves with prominent primary and secondary venation: