IB 168 – Plant Systematics

1

Laboratory 13: Rosidae – Part 1 The Rosids are one of the largest groups in the Eudicot clade. The Rosids are split into three basic groups: a basal grade of families, and the Eurosid I and Eurosid II clades (both of which are well supported monophyletic groups). Today we will be dealing with the basal grade of families, as well as the Myrtales which has an uncertain position in the Rosid clade. The orders and families we will be looking at today are: Saxifrag-ales (Saxifragaceae, Grossulariaceae, Hamamelidaceae, Altingiaceae, Crassulaceae); Vitales (Vitaceae); Geraniales (Geraniaceae); and Myrtales (Myrtaceae, Onagraceae, Melastomataceae).

Saxifragaceae Herbs; stipules typically absent; leaves generally simple and alternate,

frequently in a basal rosette; flowers usually regular and bisexual; calyx composed of 5 fused sepals; corolla composed of 5 distinct petals; stamens 5 or 10, all distinct; ovary may be either superior or inferior but is usually composed of 2 or 4 carpels, 1 style per carpel; variously developed hypanthium; fruit generally a capsule.

Tellima Bergenia Heuchera

Grossulariaceae

Shrubs; leaf margins lobed, secondary veins palmate, bases broad; flowers bisexual; raceme inflorescence; calyx compsed of 4-5 sepals; corolla composed of 4-5 petals; ovary inferior; well-developed hypanthium; fruit is baccate (fleshy or juicy).

Ribes Hamamelidaceae

Trees and shrubs; leaves alternate and simple, may be palmately lobed; stipules present, borne on the stem; flowers bisexual or unisexual; dioecious or monoecious; usually aggregated into heads or spikes; calyx composed of 4-5 united sepals; corolla composed of 4-5 distinct petals (sometimes absent); stamens usually 4-5 alternating with sterile staminodes; generally ovary is half-inferior and is composed of two fused carpels; two styles; fruit generally a capsule.

Corylopsis Exbucklandia Hamamelis

IB 168 – Plant Systematics

2

Altingiaceae Trees or shrubs; aromatic resinous compounds present in most tissues;

leaves alternate and spirally arranged, typically palmately lobed; stipules present, borne on petiole base; flowers unisexual, plants monoecious; staminate flowers lack all perianth parts, borne in terminal racemes of small globose stamen clusters; stamens numerous and elongate; carpellate flowers with scale-like tepals; borne in a globose head; stigmas 2, elongate.

Liquidambar

Crassulaceae May be herbs or shrubs, often ± succulent; leaves: simple and entire,

alternate or opposite but often arranged in a rosette; stipules lacking; flowers small, regular and bisexual; calyx composed of 4-5 free sepals; corolla composed of 4-5 free petals; stamens equal to or twice as many as petals, arranged in one or two whorls; ovary superior, composed of four or five distinct carpels, each with a single locule; fruit generally a follicle.

Sedum Aeonium Kalanchoe Echeveria

Vitaceae

Mostly vining shrubs with tendrils (either modified shoots or inflorescences); leaves simple or compound, often palmate, opposing tendrils, alternate with other leaves; stipules often present; flowers reduced, unisexual or bisexual; 4-5 sepals, often fused or united to form a cup; 4-5 petals, often joined at their tips and falling away as the flower opens; stamens equal to petal number and opposite them; ovary superior, 2 fused carpels; fruit is a berry (e.g. grapes).

Vitis Geraniaceae

Herbs or shrubs; leaves variable, often highly dissected, usually stipulate; stems jointed at the nodes; flowers bisexual and generally regular; nectaries often present; 5 sepals; 5 petals, often notched at the tip and prominently veined; stamens between 5-15 arranged in 1-3 whorls of five; ovary superior, composed of five fused carpels and five locules; styles typically fused into one, but with 5 distinct stigmas; fruit is a schizocarp (breaks apart into five indehiscent one-carpellate units), often with a prominent fruit beak.

Geranium Pelargonium Erodium

IB 168 – Plant Systematics

3

Myrtaceae Woody trees or shrubs; leaves simple, entire, generally opposite, aromatic

due to the presence of ethereal oils; stipules absent; flowers regular and bisexual; 4-5 sepals, typically very reduced; 4-5 petals, typically very reduced; stamens numerous, generally colored and very showy; ovary generally inferior with 2-5 locules, a single long style present; fruit is a berry, capsule or nut.

Eucalyptus Callistemon Leptospermum Kunzea

Onagraceae

Mostly herbaceous, a few shrubs; leaves simple, leaf insertion variable; stipules small or absent; flowers usually bisexual, radial or bilateral, typically with a conspicuous hypanthium; 4 free sepals(sometimes 2 or 5); 4 petals (sometimes 2, 5, or lacking), free, sometimes clawed (tapered at the base); stamens 8, arranged in two distinct whorls (one frequently taller than the other); ovary inferior, number of locules varies, single style, stigma entire or divided into 4 lobes; fruit generally a capsule.

Clarkia Fuchsia

Melastomataceae Mostly shrubs and small trees; leaves simple, opposite, decussate, often

having ± parallel veins; stipules absent; flowers bisexual, radial to bilateral; 4-5 sepals; 4-5 petals; stamens generally twice as many as petals; filaments bent, elbow-shaped (geniculate); anthers often curved and dehiscing by a terminal pore, usually not attached basally to the filament; ovary position and carpel number variable; fruit generally a berry or capsule.

Tibouchina Monochaetum

From: Simpson. 2006. Plant Systematics. Elsevier.

Figures from Lawrence. 1951. Taxonomy of Vascular Plants. Macmillan.

Figures from Lawrence. 1951. Taxonomy of Vascular Plants. Macmillan.