(90 



I. PlTHECOLOBIUM GuADALUPENSE (PerS.) Chapm. 



Mimosa Guadalufcnse Pers. Syn. 2: 262. 1805. 

 Pithecolobium Guadalupense Chapm. Fl. S. States. 116. 

 i860. 



In sand, Key West, Florida. Also in tropical America. 



2. Pithecolobium Unguis-Cati (L.) Benth. 



Mimosa Unguis-Cati L. Sp. PL 517. 1753- 

 Pithccolobium Unguis-Cati Benth. Lond. Journ. Bot. 3: 



200. 1844. 



In sand, southern peninsular Florida and the Keys. Also 



in tropical America. 



2. SIDEROCARPOS. 



Trees with spreading branches and zigzag twigs. Leaves 

 alternate, but often clustered : blades 2-pinnate, with 4-6 

 pinnae: leaflets relatively few. Flowers mostly perfect, in 

 cylindric spikes. Calyx campanulate, 5-lobed, very different 

 from the corolla. Corolla 5-lobed, the lobes longer than the 

 tube. Stamens numerous : filaments united below. Ovary 

 sessile : style filiform. Ovules numerous. Pods stout and 

 turgid, very tardily dehiscent, the valves woody, enclosing a 

 soft tissue which separates the seeds from each other. Seeds 

 transverse, on straight funicles. 



From mdrjpoz, iron, and xapitot;, fruit, in reference to the 

 very hard valves of the pod of the following species. 



Distinguished from related genera by the characters given 

 in the generic key. 



I. SIDEROCARPOS FLEXICAULIS (Benth.) 



Acacia flexicaulis Benth. Lond. Journ. Bot. 1 : 505. 1842. 

 Pithecolobium Texense Coult. Cont. Nat. Herb. 1: 27. 



1890. 



Pithecolobium jlexicaule Coult. Bot. Gaz. 15 : 270. 1890. 



On bluffs, Texas and adjacent Mexico. 



3. HAVARDIA. 



Small evergreen trees, sometimes shrubby, armed with 

 stipular spines. Leaves alternate : blades 2-pinnate, with 



