| 1 | Leaf apex clearly mucronate; shrubs |
| 1' | Leaf apex not clearly mucronate; shrubs or climbers |
| 2 | All leaves opposite |
| 2' | At least some leaves in whorls of 3 or more |
| 3 | Secondary veins numerous, close together and barely distinguishable from tertiary venation, > 80 pairs; leaf margin strongly undulate; sepal apices rounded |
| 3' | Secondary veins variable, 18-58 pairs; leaf margin strongly undulate to flat; sepal apices obtuse to acute |
| 4 | Leaf margin strongly undulate; corolla tube c. 2.6 mm long; stamen insertion c. 0.35 of tube length; anther apex c. 1.4 mm from corolla mouth |
| 4' | Leaf margin not undulate to weakly undulate; corolla tube 8.5-11.2 mm long; stamen insertion 0.67-0.87 of tube length; anther apex 0-1 mm from corolla mouth |
| 5 | Leaves punctate beneath |
| 5' | Leaves not punctate beneath |
| 6 | Secondary veins 33-79 pairs, tertiary venation parallel to secondary veins and weakly prominent above; inflorescence with several clear internodes and unbranched side branches; corolla bud head c. 0.43 of bud length, apex acuminate |
| 6' | Secondary veins 14-23 pairs, tertiary venation obscure; flowers solitary or inflorescence a simple unbranched pleiochasium; corolla bud head 0.26-0.37 of bud length, apex obtuse to acute |
| 7 | Flowers solitary |
| 7' | Flowers in inflorescences |
| 8 | Inflorescence a simple unbranched pleiochasium or of axillary unbranched pleiochasia and a terminal compound pleiochasium with only 1 or 2 nodes |
| 8' | No inflorescences of simple unbranched pleiochasia, all compound |
| 9 | Corolla tube ≤ 3 mm long |
| 9' | Corolla tube > 3 mm long |
| 10 | Bracteoles present |
| 10' | Bracteoles absent or only on pedicel of terminal flower in an inflorescence |
| 11 | Branchlets glabrous; corolla tube glabrous outside; leaf short to long acuminate and rounded at the tip, leaves reaching 5.1-6.6 cm long |
| 11' | Branchlets densely puberulent, corolla tube sparsely puberulent around the top of the tube outside; leaf acuminate but notched at the apex, leaves reaching c. 2.4 cm long |
| 12 | Inflorescence robust; corolla tube > 8 mm long |
| 12' | Inflorescence not robust; corolla tube ≤ 8 mm long |
| 13 | Pedicels without bracteoles; corolla tube not continuously pubescent most of tube length inside. — Not on mainland New Guinea |
| 13' | Pedicels with bracteoles; corolla tube continuously pubescent except for base inside. — Mainland New Guinea |
| 14 | Bracteoles present |
| 14' | Bracteoles absent or only on pedicel of terminal flower in an inflorescence |
| 15 | Corolla tube 3.4-6 mm long, usually pubescent outside |
| 15' | Corolla tube c. 8 mm long, glabrous outside |
| 16 | Secondary veins not visible above |
| 16' | Secondary veins distinguishable above |
| 17 | Corolla tube 4.1-5 mm long; branchlets pubescent, sometimes glabrescent |
| 17' | Corolla tube 6.3-6.9 mm long; branchlets glabrous |
| 18 | Inflorescence frequently branched and forming large, lax terminal panicles formed from axillary and terminal inflorescences, often longer than the leaves |
| 18' | Inflorescence of various sorts of compound pleiochasia but not forming large lax panicles and generally shorter than the leaves |
| 19 | Pedicels with one bracteole immediately beneath the calyx; stamens inserted above the middle of the corolla tube |
| 19' | Pedicels with two bracteoles on the pedicel or without bracteoles; stamens inserted below the middle of the corolla tube (latter character not known in A. manusiana) |
| 20 | Corolla lobes elliptic, c. 0.9 mm wide; corolla tube 1.6 times as long as lobes; stamens inserted at 1.2 mm from corolla base which is 0.52 of tube length |
| 20' | Corolla lobes ovate or orbicular, c. 1.1 mm wide; corolla tube 2.5-2.7 times as long as lobes; stamens inserted at 2.2-2.3 mm from corolla base which is 0.65-0.7 of tube length |
| 21 | Leaf margin weakly inrolled; inflorescence 3.5-7 cm long; fruit articles 5.3-7.3 mm long |
| 21' | Leaf margin flat; inflorescence 4.3-16.5 cm long; fruit articles 5.5-19 mm long |
| 22 | Sepals 1.2-1.7 mm long; ovary pubescent around base only or pubescent in tuft between carpels; fruit articles 5.5-9.9 by 4.3-6.5 mm |
| 22' | Sepals 2.1-2.9 mm long; ovary densely pubescent all over; fruit articles 11.5-19 by 8.7-13 mm |
| 23 | Inflorescence exclusively terminal |
| 23' | Inflorescence not exclusively terminal |
| 24 | Leaf apex caudate; secondary veins 50-58 pairs; inflorescence c. 2 cm long, delicate; pedicels 4-5 mm long; corolla tube c. 2.6 mm long |
| 24' | Leaf apex emarginate to acuminate and then often notched at the apex; secondary veins 28-46 pairs; inflorescence 1.1-1.5 cm long, robust; pedicels 0-0.8 mm long; corolla tube 6.7-7.4 mm long |
| 25 | Secondary veins prominent, not particularly distinct from prominent tertiary venation so appearing densely packed, ≥ 100 pairs |
| 25' | Secondary veins variable, distinct or not, sometimes obscure, < 100 pairs |
| 26 | Inflorescence glabrous, 4-9 cm long |
| 26' | Inflorescence sparsely puberulent only in upper parts to densely puberulent, 1-2.5 cm long |
| 27 | Corolla lobes ≥ 4 mm long |
| 27' | Corolla lobes < 4 mm long |
| 28 | Corolla tube > 8 mm long |
| 28' | Corolla tube < 8 mm long |
| 29 | Corolla lobes ≥ 2 times as long as wide; flowers subsessile |
| 29' | Corolla lobes < 2 times as long as wide, or if more then clearly pedicellate |
| 30 | Bracteoles present on pedicels |
| 30' | Bracteoles absent or only on pedicel of terminal flower in an inflorescence |
| 31 | Only one bracteole immediately beneath the calyx |
| 31' | Bracteoles one on pedicel, two in various positions, or several |
| 32 | Branchlets sparsely to densely minutely puberulent |
| 32' | Branchlets glabrous |
| 33 | Corolla tube c. 2.1 mm long, 1.4-1.9 times as long as lobes |
| 33' | Corolla tube 2.8-3.3 mm long, 2.5-5.1 times as long as lobes |
| 34 | Inflorescence 1.1-3 cm long with 4-12 flowers |
| 34' | Inflorescence 4-9 cm long with 16-51 flowers |
| 35 | Corolla bud head acuminate, lobes 1.9-2.8 times as long as wide |
| 35' | Corolla bud head rounded to acute, lobes 0.9-1.6 times as long as wide |
| 36 | Corolla tube < 3 mm long; fruit articles > 25 mm long; inflorescence to 9 cm long |
| 36' | Corolla tube ≥ 3 mm long; fruit articles < 25 mm long; inflorescence to 3.5 cm long |
| 37 | Flowers 13-25 in an inflorescence which is very robust; corolla tube c. 3.4 mm long, c. 3.1 times as long as lobes; leaves reaching 10.1-18 cm long |
| 37' | Flowers 3-10 in an inflorescence which is not particularly robust; corolla tube 3.4-6.2 mm long, 1.6-2.9 times as long as lobes; leaves reaching 2.5-8.7 mm long |
| 38 | Corolla tube ≥ 6 mm long |
| 38' | Corolla tube < 6 mm long |
| 39 | Corolla glabrous outside; ovary pubescent in a tuft between the carpels; leaves spathulate, sometimes obovate |
| 39' | Corolla mostly pubescent outside, rarely glabrous; ovary densely pubescent all over; leaves never spathulate |
| 40 | Leaves in whorls of 3 or 4 |
| 40' | Leaves in whorls of 5 or more |
| 41 | Corolla lobe apex acuminate; leaves strongly undulate at margin, apex long acuminate to caudate |
| 41' | Corolla lobe apex rounded to acute; leaf margin variable, apex variable but rarely long acuminate |
| 42 | Inflorescence with 25 or more flowers in an inflorescence |
| 42' | Inflorescence with 3-16 flowers in an inflorescence |
| 43 | Inflorescence glabrous |
| 43' | Inflorescence sparsely to densely puberulent |
| 44 | Ovaries pubescent in a tuft between the carpels or very sparsely pubescent only around the base; fruits with up to 7 articles in a chain |
| 44' | Ovaries pubescent all over or densely pubescent only around base; fruits with only up to 2 articles in a chain |
| 45 | Largest leaves on a plant at least 8.6 cm long |
| 45' | Leaves no longer than 8 cm long |
| 46 | Ovaries glabrous or pubescent only in a tuft between carpels; corolla lobes 0.7-1 mm wide |
| 46' | Ovaries densely pubescent all over to pubescent around base; corolla lobe 1.1-2.3 mm wide |
| 47 | Branchlets glabrous |
| 47' | Branchlets sparsely to densely puberulent |
| 48 | Bracts 0.9-1 mm long |
| 48' | Bracts 1.6-5 mm long |
| 49 | Corolla sparsely to densely pubescent outside; fruit articles 12.8-21.5 mm long |
| 49' | Corolla glabrous outside; fruit articles 9-10.5 mm long |
| 50 | Corolla tube 1.8-3.8 mm long; leaf apex not folded back; 1.6-9.3 mm between fruit articles |
| 50' | Corolla tube 4.1-5 mm long; leaf apex often folded back; 0-1 mm between fruit articles |
