General description:- Shrubs or herbs.
Leaves:- Simple, usually opposite, mostly with stellate indumentum.
Flowers:- Hermaphrodite, radially symmetrical (actinomorphic), the sepals, petals and stamens inserted on the receptacle below and free from the ovary (hypogynous), solitary or in cymes. Sepals 5 or 3. Petals 5, rarely 0, usually falling off early (caducous). Stamens many. Ovary single-celled (1-locular) or incompletely septate with 3 or 5 (rarely 10) parietal placentae; ovules usually with a straight axis, the base of the nucellus proximal, the micropyle distal (orthotropous), rarely reversed i.e.bent parallel to its stalk (anatropous). Style simple or absent.
Fruit:- A loculicidal capsule. Seeds with a more or less curved embryo; endosperm present.
Genus: CISTUS
General description:- Shrubs.
Flowers:- 2 cm or more diam, white to purplish-red. Ovary usually 5-, rarely up to 10-locular; placentation axile; ovules orthotropous, the seed stalk (funicle) thread-like (filiform).
Key features:-
1) Capsule with 5, 6 or 10 valves.
2) Flowers white to purplish-red.
All species are plants of dry scrub or open woodland.
Genus: FUMANA
General description:- Dwarf shrubs.
Leaves:- Narrow, ovate-lanceolate to linear, acicular, alternate (rarely opposite), stipulate or exstipulate.
Flowers:- The two outer sepals small, the three inner large, thin and dry (scarious), prominently veined. Petals yellow. Outer stamens sterile, like a string of beads, (moniliform). Style thread-like (filiform), more or less abruptly bent knee-like(geniculate) at the base.
Fruit:- Capsule 3-veined, the valves usually patent after splitting open to release the seeds (dehiscence).
Key features:-
1) Upper leaves usually alternate, ± linear; outer stamens sterile; ovules anatropous.
All European species grow on dry, rocky, stony or sandy ground, often in low scrub.
Genus: HELIANTHEMUM Including Subgen. HELIANTHEMUM Incl-Sects BRACHYPETALUM and ARGYROLEPIS, Subgen. PLECTOLOBUM Incl, Sect. PLECTOLOBUM.
General description:- Dwarf shrubs or annual herbs.
Leaves:- Opposite, the alternate pairs are at right angles to each other (decussate), usually stipulate.
Flowers:- In raceme-like cymes, often directed towards one side (secund). Sepals 5, the 3 inner ovate, the 2 outer smaller, usually linear or oblong. Petals usually yellow, less often white or pink; stamens numerous, all fertile. Style short and straight or thread-like (filiform) and more or less S-shaped (sigmoid).
Fruit:- Capsule ovoid, 3-valved; ovules with a straight axis (orthotropous).
1) Dwarf shrubs or annuals, without a basal leaf-rosette; style present
2) Leaves all opposite and decussate, oblong to linear; stamens all fertile; ovules orthotropous
Subgen. HELIANTHEMUM
Leaves:- All stipulate.
Flowers:- Style straight or slightly sigmoid.
Sect. ARGYROLEPIS
Sect. BRACHYPETALUM
Flowers:- Inflorescence mostly unbranched. Style short, straight.
Fruit:- Capsule trigonous.
Subgen. PLECTOLOBUM
Dwarf shrubs; at least the lower leaves exstipulate; style distinctly sigmoid at the base.
Sect. PLECTOLOBUM.
Flowers in simple or branched, bracteate cymes.
Sect. ARGYROLEPIS
General description:- Shrubs or dwarf shrubs.
Flowers:- Inflorescence compound.
Fruit:- Capsule ellipsoid-trigonous.
Genus: TUBERARIA Including: Sect. SCORPIOIDES
General description:- Annual or perennial, with a basal leaf-rosette.
Stems:- Flowering erect.
Leaves:- With 3 veins.
Flowers:- Yellow, in terminal cymes. Sepals 5, the 2 outer usually smaller than the 3 inner. Stigma more or less sessile.
Fruit:- Capsule 3-valved.
Distinguishing features:-
1) Style long, or if short or 0 then herbs;
2) Sepals 5
3) Basal leaf-rosette (which may be withered at anthesis);
4) Stigma stalkless or short-stalked (sessile or subsessile).
Sect. SCORPIOIDES
Leaves:- Uppermost, usually stipulate.
Flowers:- Ovary sessile.