Part 3, 1911] RUTACEAE 179 



Blade of the petiole 7-20 mm. broad, elliptie-obovate to 

 broadly obovate ; leaflets 1 or 3, or wanting, sub- 

 eoriaceous. 16. Z . phyllopterum. 



Blade of the petiole 1-6 mm. broad, oblong to oval or 

 occasionally somewhat obovate ; leaflets 2, rarely 3, 

 rigid. 17. Z. ditmosum . 



Leaflets 3-13, callus-bearing at the base ; petiole and rachis 

 wing-margined, commonly distinctly narrower than the 

 leaflets. 

 Wing of the rachis obscurely veined ; prickles straight. 18. Z. spinifex. 

 Wing of the rachis reticulate-veined ; prickles recurved. 19. Z. tragodes. 

 Flowers paniculate, spicate, or racemose. 



Leaflets 2-17, broadest above the acute or cuneate base, 

 rarely rounded. 

 Leaves" odd-pinnate, rarely equally pinnate through the 

 abortion of the terminal leaflet ; seeds black. 

 Leaflets 3, rarely 5. 



Leaflets obovate, occasionally elliptic to nearly or- 

 bicular, 0.7-3 cm. long, 0.4-1.4 cm. broad, often 



obtuse or rounded at the apex. 20. Z. Litbmannianum . 



Leaflets oblong-elliptic to lance-elliptic, 2-7.5 cm. 

 long, 1.5-2.9 cm. broad, commonly pointed at the 

 apex. 21. Z. Limoncello. 



Leaflets 5-17, usually 7 or more. 



Flowers usually in terminal or lateral panicles or in 

 long slender racemes. 

 Leaflets crenulate, commonly obovate. 



Calyx apparently of oblong or oblong-ovate 



distinct, deciduous sepals. 45. Z. Purpusii* 



Calyx of triangular or suborbicular lobes, 

 persistent beneath the follicles. 

 Leaflets 7-15, becoming blackish or dark- 

 brown in drying ; follicles 5-7 mm. long; 

 seeds 3.5-5 mm. in diameter. 22. Z. insulare. 



Leaflets 5-7, becoming light or yellowish- 

 green in drying ; follicles 3.5-4 mm. long ; 

 seeds 2.5-3 mm. in diameter. 23. Z. Culanlrillo. 



Leaflets entire or minutely repand, ovate to oval. 

 Lateral leaflets callus-bearing at the base, 2- 

 4.6 cm. long, 1-2.2 cm. broad, glabrous; 

 branches of the inflorescence minutely pu- 



berulous; calyx of persistent sepals. 24. Z. Harmsianum. 



Lateral leaflets not callus-bearing at the base, 

 4-8.5 cm. long, 2-4 cm. broad ; branches of 

 the inflorescence densely ferruginous-pilose; 



calyx apparently of free sepals, deciduous. 47. Z. mollissimiini* 

 Flowers in short, often lateral spikes or spike-like 

 racemes, usually less than 2 cm. long. 

 Follicles small, the valves 3.5-4 mm. broad, the 

 stipe usually long and slender ; rachis com- 

 monly glabrous. 25. Z. Fagara. 

 Follicles large, the valves 4-5.5 mm. broad, the 

 stipe short and stout; rachis usually puberulent. 26. Z. affine. 

 Leaves equally-pinnate ; seeds reddish or blackish-red. 27. Z. Rhodoxylon. 

 Leaflets 15-61, broadest at the truncate or subtruncate base. 

 Inflorescence lateral, axillary ; follicles 5-7 mm. in diam- 

 eter ; seeds 4—1.2 mm. long; leaflets 5-19 mm. long, 3-10 

 mm. broad, 15-31. 28. Z.foliolosum. 

 Inflorescence terminal or lateral in the axils of the upper 

 leaves; follicles 4 mm. in diameter; seeds 3 mm. long, 



leaflets 4-9 mm. long, 3-5 mm. broad, 25-61. 29. Z. elegantissimum . 



2. Sepals, petals and stamens 5 (rarely 4 in a few flowers of the 

 same inflorescence). 

 Leaves unifoliolate. 30. Z. monophyllum. 



Leaves several-foliolate, abnormally unifoliolate. 



Leaves 0.5-1.5 cm. long; leaflets 2.5-7 mm. long, 1-4 mm. 



broad ; flowers solitary, axillary, closely sessile. 31. Z. Nashii. 



Leaves and leaflets decidedly larger ; flowers few to many, on 

 distinct peduncles. 

 Sepals suborbicular or triangular-orbicular, strongly im- 

 bricate in flower ; carpels 5. 

 Branches of the inflorescence corky-thickened ; plants 

 glabrous or nearly so. 

 Seeds 6-8 mm. long, 5.5-6.5 mm. broad ; follicles 9- 

 15 mm. long, 6-10 mm. broad, the body obovoid 

 or nearly orbicular ; leaflets mostly tapering to 

 an acuminate tip. 

 Follicles sessile. 32. Z. Nehoni. 



* These species are repeated in the key because the number of the sepals is doubtful. 



