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Electronic Flora of South Australia family Fact Sheet

Rubiaceae

Alternative names: Not Applicable

Description:
Herbs, shrubs or rarely trees, often with angular stems; leaves entire, opposite, with interpetiolar stipules which are sometimes indistinguishable from leaves (then the collective term 'leaves' is used).

Inflorescence a thyrse or dichasium, rarely fused into a flower head or a single terminal flower, bisexual or unisexual and monoecious or dioecious; sepals 4 or 5, often rudimentary or absent; petals 4 or 5, tubular and connate with the filaments at least at the base; stamens 4 or 5, alternate with the petals; ovary inferior, rarely semi-inferior, with 2 locules each with one to many anatropous ovules on central placentas; style single or 2-fid, with capitate, filiform or mitre-shaped stigmas.

Fruit usually either a capsule, drupe or schizocarp; seeds usually with endosperm.

Distribution:  About 500 genera and up to 7,000 species found in most parts of the world but particularly well represented in tropical and subtropical regions.

Biology: No text

Key to Genera:
1. 'Leaves' in whorls of 3-12
 
2. Inflorescence a dense terminal head surrounded by a leaf-like involucre; calyx present
SHERARDIA 9.
2. Inflorescence axillary or if terminal then without a leaf-like involucre; calyx absent
 
3. Corolla usually funnel-shaped; fruits fleshy, indehiscent
ASPERULA 1.
3. Corolla rotate with a very short tube; fruit dry, breaking into 2 mericarps
GALIUM 5.
1. Leaves opposite
 
4. Inflorescence an umbel and/or a capitulum; fruits compound, dehiscing with a lid
 
5. Inflorescence a hemispherical to spherical head; compound fruit dehiscing with many irregular and often oblique lids
OPERCULARIA 7.
5. Inflorescence apparently umbellate with few to many flower-like connate part-inflorescences; compound fruit dehiscing with a single round lid
POMAX 8.
4. Inflorescence a thyrse or dichasium or rarely single flowers; fruit simple, if dehiscing then without a separate lid
 
6. Woody shrubs or trees
 
7. Stipules sheathing the terminal bud and scarcely fused to the petioles; plants monoecious; semi-arid regions
CANTHIUM 2.
7. Stipules fused to the petioles to form a sheath around the node; plants dioecious; coastal higher rainfall regions
COPROSMA 3.
6. Herbs rarely with a slightly woody base
 
8. Flowers sessile at the nodes
 
9. Fruit fleshy; leaves membranous or almost so
NERTERA 6.
9. Fruits dry; leaves fleshy
DENTELLA 4.
8. Flowers stalked or on a stalked inflorescence
 
10. Fruits fleshy; plants dioecious; corolla tube usually as long as or longer than the lobes
ASPERULA 1.
10. Fruits dry; plants monoecious; corolla tube almost absent
 
11. Calyx absent; fruit breaking into two 1-seeded mericarps
GALIUM 5.
11. Calyx present; fruit dehiscing by a loculicuidal split to release numerous seeds
SYNAPTANTHA 10.

Author: Prepared by H. R. Toelken


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