218 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
longer, distinctly broadened at the apex, and hardly, if at all, stipitate; the 
teeth may also be longer, narrower, and closer together. Similar variations 
can be observed in the shape, size, and indument of the leaflets, or in the 
arrangement of other parts, notwithstanding which we find it difficult to dis- 
criminate between the specimens, because these variations are combined in 
every possible way, some characters remaining constant all through the 
series. Certain forms could be separated, as has been done in other old 
polymorphic species of the temperate regions, split to-day into no end of so- 
called new species, but this goes against any rational definition of a specific 
unit, and besides this we are still in ignorance as to the environmental condi- 
tions under which these forms develop. 
The reestablished species are Inga paucifora Walp. & Duchass., a well- 
defined Panama type leaning perhaps to the J. edulis group, and J. eriocarpa 
Benth., distinguished from I. ralapensis Benth. by its larger flowers and the 
tomentose indument of the calyx. 
LIST OF THE KNOWN SPECIES OF INGA. 
The following enumeration includes all the species of Inga re- 
garded by the writer as valid, described up to the present date, with 
indication of the origin of the type. The species marked with an 
asterisk are those not represented in the American herbaria con- 
sulted. 
Section 1. LEPTINGA. 
1, Inga boliviana Britton, Bull. Torrey Club 17: 9. 1890. Bolivia. 
2. *brevipes Benth. Journ. Bot. Hook. 2: 144. 1840. British Guiana. 
3. *cynometrifolia Harms, Verh. Bot. Ver. Brand. 48: 158. 1907. Peru. 
4, flagelliformis (Vell.) Mart. Flora 20: Beibl. 112. 1887. Brazil. 
5. *graciliflora Benth. Lond. Journ. Bot. 4: 582. 1845. British Guiana. 
6. heterophylla Willd. Sp. Pl. 4: 1020. 1806. Brazil. 
7%. *“lallensis Spruce; Benth. Trans. Linn. Soc. 30: 603. 1875. Peru. 
8. lateriflora Miquel, Linnaea 19: 131. 1847. Surinam. 
9. mapiriensis Pittier, above, p. 174. Bolivia. 
10, maxoniana Pittier, above, p. 174. Venezuela. 
11. myriantha Poepp. & Endl. Nov. Gen. & Sp. 3: 77. pl. 289. 1845. 
Peru. 
12. panurensis Spruce; Benth. Trans. Linn. Soc. 30: 602. 1875. Brazil. 
13. *pardoana Harms, Bot. Jahrb. Engler 42: 89. 1908. Peru. 
14, portobellensis Beurling, Svensk. Vet. Akad. Handl. 1854: 122. 1856. 
Panama. 
15. quaternata Poepp. & Endl. Nov. Gen. & Sp. 3: 79. 1845. Peru. 
16. roussoviana Pittier, above, p. 175. Panama. 
17. saffordiana Pittier, above, p. 176. Panama. 
18, sciadion Steud. Flora 26: 758, 1843. Cayenne, French Guiana. 
19, sellowiana Benth. Lond. Journ. Bot. 4: 583. 1845. Brazil, 
20. sertulifera DC. Prodr. 2: 436. 1825. *Brazil. 
21. tarapotensis Spruce; Benth, Trans. Linn. Soc. 30: 609. 1875. Peru. 
22. umbellifera (Vahl) Steud.; DC. Prodr. 2: 432. 1825. French Guiana. 
23. *umbratica Poepp. & Endl. Nov. Gen. & Sp. 3: 77. 1845. Peru. 
24. virgultosa (Vahl) Desv. Ann. Sci. Nat. 9: 426. 1826. French Guiana. 
25. williamsii Pittier, above, p. 176. Panama. 
26. “wittiana Harms, Verh. Bot. Ver. Brand. 48: 161, 1907, Brazil. 
