78 



MEMOIRS OF THE NEW YORK BOTANICAL GARDEN 



[VOL. 10 



5. Filaments more or less pubescent, sometimes only basally so. 6. 



5. Filaments glabrous. 15. 



6. Bracteoles pubescent on the inner surfaces (sometimes only sparingly so near the 

 apex). Leaflets 8-40-jugate. 7. 



6. Bracteoles glabrous on the inner surfaces. Leaflets 6-7- jugate 11'. M. a/nomalum. 



7. Inflorescence less than 2 cm long. 8. 



7. Inflorescence longer than 2 cm. 9. 

 S. Median leaflets four or more times as long as wide, essentially glabrous, 20-30- 



jugate. 2c. M. gracile var. dcbile. 



8. Median leaflets three times as long as wide, pubescent on both sides, mostly 15- 

 jugate. 2d. M . gracile var. graciU . 



9. Leaflets obviously emarginate or retuse apically. 10. 

 Leaflets entire apically. 14. 



10. Leaves lanceolate to oblong lanceolate in outline, the leaflets with the costa salient. 11. 



10. Leaves oblong in outline, costa salient or not. 12. 



11. Inflorescences pilosulose ; outer surfaces of the bracteoles pilose and flexuose- 

 pilosulose. 4. M. brevense. 



11. Inflorescences puberulous; flowers not known. 2b. M. gracile var. machadocnse. 



12. Median leaflets about 4 cm long, 1.5 cm wide, the venules prominulous. 



11. M. flexuosum & var. 



12. Median leaflets usually less than 2.5 cm long, 1 cm wide, the venules obscure to 

 subobscure. 13. 



13. Upper side of leaflet base angular-aurieulate, the apex strongly emarginate. 



3. M. machaerioides. 



13. Upper side of leaflet base obtuse, the apex truncate-obtuse, retuse to emarginate. 



10. M. venulosum. 



14. Leaflets evenulose, the lower surface cano-strigulose. Bracts 5.5-7 mm long, elliptic- 

 lanceolate. 10'. M. evenulosum. 



14. Leaflets at least faintly venulose, the lower surface glabrous or somewhat jdlosu- 



lose. Bracts 2.5-3 mm long, triangular-ovate 2a. M. gracile var. confcrtum. 



15. Bracteoles pubescent on both surfaces. 16. 



15. Bracteoles pubescent on outer surface only. 17. 



16. Leaf rachis 3-3.5 cm long; leaflets about ten times as long as wide, the apex entire. 



2'. M. cataractarum. 



16. Leaf rachis 9-15 cm long; leaflets 2-3 times as long as wide, the apex retuse. 



9. M. froesii. 



17. Costa of leaflets distinctly salient on both surfaces. Bracteoles and pedicels lanu- 

 lose-puberulous. Fruit three to four times as long as wide. 7. M. longeracemosum. 



17. Costa impressed on the upper surface of the leaflets. Bracteoles and pedicels 



pilosulose. Fruit about one and a half times as long as wide. 8. M. acaciaefolium. 



Key to the Species of Series 2a 



1. Leaflets with the venules closely parallel and prominulous on both surfaces, the 

 intramarginal nerve originating from the base of the costa, the apex strongly emar- 

 ginatf, rounded. 30. M. retusum. 



1. Leaflets with the venules obscure or, if prominulous, not closely parallel, the intra- 

 marginal nerve formed by the anastomosing of primary veins, the apex entire, acute 

 to acuminate. 25. M. limbatum & vars. 



Key to the Speeies of Series 2b 



1. Hairs of pubescence minutely ribbon-like, peg-like, or clavate (sub lente). 2. 



1. Hairs of pubescence cylindric, • neither clavate, ribbon-like, or peg-like. 4. 



2. Hairs ribbon-like. Bracteoles thin, never fleshy. 27. M. bifolium. 



2. Hairs peg-like or clavate. Bracteoles thick, spongy-fleshy. 3. 



3. Hairs clavate. Leaflets to 15 cm long and 7 cm wide. Inflorescence axillary. 



28. M. laUfoUum. 



3. Hairs peg-like. Leaflets 32-39 cm long and 12-14 cm wide. Inflorescence 

 ramuliflorous. 28'. M. wurdachii. 



4. Inflorescences axillary to pseudo-terminal ; sepals 5. 5 



4. Inflorescences cauliflorous to ramuliflorous; sepals 4. 6 



5, Leaflets strongly cordate at the lower side of the inequilateral base, rigid- 

 coriaceous. Bracts 2.5 mm long, oblong ovate. 31. M. duckeanwm 



