STANDLEY TREES AND SHRUBS OF MEXICO. 383 



DOUBTFUL SPECIES. 



ACACIA CYLiNDRiFLOEA Mart. & Gal. Bull. Acad. Brux. 10 ^ 313. 1843. Type 

 from Oaxaca. Probably a Mimosa. 



Acacia feeox Mart. & Gal. Bull. Acad. Brux. 10=": 314. 1843. 



Acacia lanata Mart. & Gal. Bull. Acad. Brux. 10^: 315. 1843. Type from 

 Mixteca Alta. 



Acacia mollicula Mart. & Gal. Bull. Acad. Brux. 10': 315. 1843. Type from 

 TehuacS,n, Puebla. Flowers said to be pink. Probably of some other genus. 



10. CALLIANDRA Benth. in Hook. Journ. Bot. 2: 138. 1840, 

 Unarmed shrubs or small trees, or sometimes herbs; leaves bipiunate, the 

 leaflets small or large ; stipules usually persistent ; flowers in dense heads, often 

 rather large and showy, red or white, the stamens long-exserted ; fruit flat, 

 usually straight, the valves recurved after dehiscence. 



The names " plumita " (Oaxaca) and " gavia " (Durango) are reported for 

 undetermined species of the genus. 

 Leaflets 2 to 4 to each pinna, mostly 2 to 7 cm. long ; pinnae usually 2 pairs. 



Leaflets pinnately nerved, lanceolate or narrowly lanceolate 1. C. laevis. 



Leaflets palmately nerved, with 2 or more distinct nerves rising from the 

 base. 



Corolla pubescent 2. C. canescens. 



Corolla glabrous 3. C. emarginata. 



Leaflets 5 to many to each pinna, often very small ; pinnae 1 to many pairs. 

 Heads of flowers in long terminal racemes ; flowers pedicellate ; filaments red 

 or purple. 

 Leaflets not falcate, roundetl or very obtuse at apex ; pinnae usually 15 to 

 20 pairs. 



Corolla appressed-pilose 4. C. anomala. 



Corolla glabrous 5. C. calothyrsus. 



Leaflets falcate, usually acute; pinnae usually 7 to 12 pairs. 



Corolla about 16 mm. long, white outside with dense appressed hairs. 



6. C. palmeri. 

 Corolla 5 to 11 mm. long, not white outside, the pubescence mostly of 



brownish hairs 7. C. houstoniana. 



Heads of flowers mostly axillary, never racemose ; flowers sessile or nearly so. 



Pinnae one pair, the leaflets large, 1 to 2.5 cm. wide 9. C. conzattii. 



Pinnae 2 or more pairs, or if a single pair the leaflets 5 mm. wide or nar- 

 rower. 

 Leaflets variously pubescent beneath. 



Leaflets large, most of them 0.8 to 2.5 cm. wide, membranaceous. 



17. C. penduliflora. 

 Leaflets small, less than 5 mm. wide, often coriaceous. 

 Plants low, less than 20 cm., woody only at the base. 



16. C. humilis. 

 Plants usually large, woody throughout. 



Leaflets oval or obovate-oval 18. C. malacophylla. 



Leaflets oblong or narrowly oblong. 

 Pinnae usually 8 to 10 pairs ; leaflets somewhat tomentose be- 

 neath with somewhat matted, curled hairs 8. C. nitida. 



Pinnae 1 to 6 pairs ; leaflets pilose beneath with mostly straight 

 appressed hairs. 

 Corolla glabrous or nearly so, greenish. 



Pinnae 1 or 2 pairs ; leaflets 6 to 10 pairs 20. C. angelica. 



Pinnae 4 to 6 pairs; leaflets 20 or more pairs 21. C. laxa. 



