Family: Lamiaceae
Prostanthera
Citation:
Labill., Nov. Holl. Pl. Sp. 2:18 (1806).
Derivation: Greek prostheke, appendage; antheros, flowery; botanical Latin anthera, anther; alluding to the small appendage of the anthers.
Synonymy: Not Applicable Common name: Mintbushes.
Description:
Small shrubs, to c. 2 m high; branches and leaves with oil glands which are usually strongly scented when crushed (P. behriana lacks odour); leaves opposite; venation and midrib usually not visible, sometimes faint.
Inflorescence raceme-like on leafy branches; part-inflorescence 1-flowered with accessory buds sometimes present; prophylls (bracteoles) 2, opposite, rarely alternate; calyx 2-lipped to 2-lobed; corolla distinctly 2-lipped, 5-lobed; lower median lobe directed outwards and forward to recurved, usually emarginate; lateral lobes spreading to reflexed; upper median lobe-pair directed outwards and forward, concave in section, often reflexed distally; stamens 4; filaments ligulate to subterete, usually glabrous, white; anthers basifixed between the lobes, 2-locular, introrse; connective often extended to form 1 or 2 basal appendages; ovary cup-shaped to cylindrical, 4-lobed, often glandular distally; style terminal, slender, ligulate to terete, slightly incurved, lying next to upper surface of the corolla; stigma shortly 2-fid.
Fruiting calyx often greatly enlarged; lower lobe inward folded (section Prostanthera) or directed outwards and forward (section Klanderia); mericarps 4, usually reticulate-rugose; seeds slightly flattened, ellipsoid to cylindrical-ellipsoid, slightly incurved, 1-2.5 mm long, 0.2-0.8 mm wide, thickened distally.
Distribution:
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About 80 species, endemic to Australia. (B. J. Conn (1984) J. Adelaide Bot. Gard. 6:207-348).
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Biology:
No text
Key to Species:
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1. Corolla with lower median lobe longer than the upper median lobe-pair; corolla white, pale-blue, mauve, purple, sometimes with a tinge of pink; calyx with lower lobe folded inwards over the mericarps, upper lobe significantly longer than the lower lobe [section Prostanthera] |
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2. Branches with spines present |
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3. Calyx lobes very unequal; shrub glabrous except for a few hairs at the distal nodes; branching more or less patent and distant |
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P. nudula 8. |
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3. Calyx lobes more or less equal in length; shrub usually hairy; branching more or less erect and relatively crowded |
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P. spinosa 10. |
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P. baxteri var. sericea 2. |
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4. Leaves more or less flat or incurved, not terete |
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5. Upper calyx lobe more or less equal to lower calyx lobe; leaves 1.5-2.5 mm long |
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P. eurybioides 6. |
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5. Upper calyx lobe much longer than the lower calyx lobe; leaves at least 4 mm long, rarely as short as 2.8 mm |
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6. Pedicels, bracteoles and calyces glabrous or sparsely hairy; corolla white with purple striations |
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P. striatiflora 11. |
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6. Pedicels, bracteoles and calyces moderately to densely hairy; corolla a mauve pale-violet, blue to white, purple striations may be present |
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7. Calyx not enlarged in fruit; leaves sparsely to densely hairy sometimes sparsely hairy adaxially, often glabrous abaxially |
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P. behriana 3. |
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7. Calyx enlarged in fruit; leaves sparsely to densely hairy on both surfaces |
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8. Hairs appressed to patent, antrorse to retrorse, hence indumentum appearing scruffy |
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P. wilkieana 12. |
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8. Hairs appressed, antrorse, hence indumentum appearing more or less smooth |
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9. Bracteoles 3.8-8.1 mm long, 0.4-1.1 mm wide; branches, leaves and calyces silky |
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P. sp. A 13. |
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9. Bracteoles 0.7-3.6 mm long, 0.1-0.4 mm wide; branches silky, leaves and calyces usually not appearing silky |
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P. sp. B 14. |
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1. Corolla with lower median lobe more or less equal to upper median lobe-pair; corolla red, orange, yellow, or dark (metallic) blue-green, rarely mauve; calyx with lower lobe remaining more or less directed outwards and forward or recurved, not enclosing the mericarps, lobes more or less equal in length [section Klanderia] |
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10. Hairs irregularly branched, more or less densely covering branches, leaves, pedicels and calyx (simple hairs may also be present) . P. chlorantha 5 |
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10. Hairs simple, sometimes with a few branched hairs on the calyx (KI populations of P. serpyllifolia subsp. microphylla), never on branches or leaves |
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11. Hairs of branches, leaves and calyces stiff, straight, appressed and antrorse |
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P. calycina 4. |
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11. Hairs of branches, leaves and calyces more or less soft, recurved to reflexed, never appressed, frequently curled |
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12. Leaves ovate to narrowly ovate, sometimes suborbicular |
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P. serpyllifolia 9. |
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12. Leaves more or less terete to linear-obovate |
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13. Anther appendage 1-2.5 mm long; calyx 7-12 mm long |
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P. florifera 7. |
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13. Anther appendage to 0.3 (rarely to 0.5) mm long; calyx 5-7 mm long |
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P. aspalathoides 1. |
Author:
Not yet available
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