General description:- Predominantly woody tropical family represented in Europe, by more or less herbaceous plants with leaf-like stipules.
Leaves:- Nearly always opposite, simple, entire; stipules separate, joined margin to margin (connate) or divided, sometimes leaf-like and then forming whorls of 4-12 apparent leaves.
Flower:- Radially symmetrical (actinomorphic), usually hermaphrodite. Inflorescence a compact panicle of ± cylindrical form (thyrsoid), or with the lower branches longer than the upper so that all end up at the same level (corymbose), sometimes condensed to a spike or head, or reduced. Sepals usually free, sometimes reduced or absent. Petals united (sympetalous); corolla with slender tube and abruptly widening limb (hypocrateriform), funnel-shaped (infundibuliform), cup-shaped or rotate. Stamens united with the petals (epipetalous), alternating with the lobes of the corolla. Ovary inferior, usually with 2 compartments (2-locular) and with a disc; loculi with 1-numerous ovules. Style simple or divided at the tip in two (usually equal) parts by a median cleft (2-fid).
Fruit:- Dry, splitting away at maturity as a perfect fruit (mericarp), or fleshy. Seeds, the nutritive tissue is absorbed more slowly into the developing embryo so that part of it remains at least until germination (endospermic).
GALLIUM
General description:- Dwarf shrubs, perennial herbs or annuals.
Stems:- More or less distinctly 4-angled and sometimes circular in cross section (terete), sometimes with small prickles or sharp points turned downward (retrorsely aculeolate); ultimate branches of inflorescence often without bracts, always without bracteoles; stems (pedicels) often longer than ovary or fruit.
Leaves:- In whorls of 4-8(-11) or in pairs.
Flowers:- Usually hermaphrodite, (3-)4-petalled (merous); corolla rarely funnel-shaped (infundibuliform), usually cup-shaped or rotate. Calyx absent or consisting of short teeth. Ovary ovoid, sometimes with hooked hairs; Inflorescence of panicles or capitula. Stigmas pin-headed (capitate) or club-shaped, i.e. thickened towards the apex (clavate).
Fruit:- Dry, rarely somewhat fleshy; ovoid.
Key features:-
1) Pedicels without bracteoles.
2) Ovary and fruit ovoid.
3) Ultimate inflorescence-branches without bracts or bracteoles.
4) Corolla 4-lobed.
5) Fruit dry.
6) Central flower of cymes hermaphrodite; lateral flowers male (rarely absent).
7) Leaves in whorls of more than 4.
Sect. ORIENTIGALIUM
General description:- Perennial herbs, often with filiform stolons.
Stems:- 4-angled, glabrous or hairy but never retrorsely aculeolate.
Leaves:- In whorls of (5-)6-7(-8), 1-veined, obtuse, acute or with a hyaline apex.
Flowers:- Inflorescence few-flowered, with usually ebracteate ultimate branches, sometimes reduced to single axillary flowers; pedicels stout, erect and not divaricate in fruit. Corolla infundibuliform or cup-shaped, white or pink; lobes acute or obtuse. Ovary usually glabrous, smooth or finely granulate.
Fruit:- Usually glabrous, smooth or finely granulate.