Here’s a detailed guide for Aquilaria and Gyrinops species identification**, which is critical for sustainable agarwood cultivation, research, and trade compliance:
1. General Overview
| Feature | Aquilaria | Gyrinops |
|---|---|---|
| Family | Thymelaeaceae | Thymelaeaceae |
| Distribution | Southeast Asia: Indonesia, Malaysia, Thailand, Cambodia, Vietnam, Philippines | Indonesia, Papua New Guinea, parts of India, and Pacific islands |
| Common Uses | Agarwood resin, incense, essential oils | Agarwood resin, incense, perfumery |
| Tree Size | Medium to large trees (10–40 m) | Usually smaller trees/shrubs (8–25 m) |
| Bark | Smooth to rough; gray-brown | Smooth to slightly fissured; brown to grayish |
| Leaf Arrangement | Alternate, simple, entire | Alternate, simple, entire |
| Flowers | Small, axillary, white or yellowish | Small, axillary, yellowish to greenish |
| Fruit | Capsule, 1–2 cm, dehiscent | Capsule, slightly smaller, often 1–1.5 cm |
2. Morphological Identification
A. Leaves
- Aquilaria:
- Length: 5–15 cm
- Width: 2–6 cm
- Shape: Lanceolate to elliptic
- Texture: Leathery
- Color: Dark green above, lighter below
- Gyrinops:
- Length: 4–12 cm
- Width: 1–4 cm
- Shape: Narrowly elliptic or oblong
- Texture: Slightly thinner, papery
- Color: Green, often with a glossier upper surface
B. Bark
- Aquilaria: Gray-brown, smooth in young trees, fissured in older trees
- Gyrinops: Brown to gray, often smoother and thinner than Aquilaria
C. Flowers
- Aquilaria: Small (0.5–1 cm), clustered in leaf axils, fragrant
- Gyrinops: Slightly smaller, less conspicuous, greenish-yellow
D. Fruit / Seeds
- Aquilaria: Brown capsules, 2–3 valves, seeds winged for wind dispersal
- Gyrinops: Slightly smaller capsules, usually single-seeded
3. Resin Formation (Agarwood)
- Both genera produce agarwood after wounding or fungal infection.
- Visual identification: The heartwood of resinous Aquilaria is darker and denser than Gyrinops.
- Smell: Slightly sweeter, more intense in Aquilaria; Gyrinops resin is milder.
4. Molecular / DNA-Based Identification
- Why important: Morphological traits may overlap; species-level ID often requires molecular tools.
- Techniques:
- DNA barcoding: Using rbcL, matK, ITS2 gene regions
- PCR markers: Species-specific primers for Aquilaria vs. Gyrinops
- Microsatellite (SSR) analysis: For population genetics and provenance
5. Practical Field Tips
- Check leaves and bark carefully; these are the easiest field markers.
- Flowers and fruits are seasonal; plan identification visits accordingly.
- Note local names; in Indonesia/Malaysia, “gaharu” can refer to both genera.
- Resin type can help confirm genus: dark, heavy, aromatic resin often indicates Aquilaria, but chemical analysis is needed for precision.
If you want, I can make a side-by-side field ID chart with illustrations showing leaf, bark, flower, and fruit differences between Aquilaria and Gyrinops species. This is extremely helpful for farmers, researchers, and trainers.
Do you want me to create that visual chart?