safford: myrmecophilous acacias 361 



at its union with the thickened upper extremity of the peduncle. Flowers 

 about 2.2 mm. long when mature, funnel-shaped, the calyx with usually 



5 shallow^ rounded lobes, glabrous near the base, puberulous about the 

 margin; corolla about one-fourth longer than the calyx and distinctly 

 separate from it, usually acutely 6-lobed, coarsely puberulent outside. 

 Interfloral pedicelled bracteoles with orbicular peltate laminae. These 

 subentire or the margin shallowly and obtusely toothed. Fruit not 

 observed. Large spines ivory white or ecru, V-shaped or spreading 

 like the horns of an ox, terete, 4 to 5 cm. long, 7 mm. broad at the 

 base. Small spines of the flowering branchlets acicular or subulate, 

 7 mm. long. Vegetative leaves with 6 to 10 pairs of pinnae, the rachis 



6 cm. long or less (in the type material), puberulent, bearing a row of 2 

 to 7 conoid nectar glands below the basal pair of pinnae, the glands 

 having a porelike openmg surromided by a smooth, whitish, circular or 

 elliptical, annular margin; pinnae 15 mm. long or less; leaflets of the 

 longer pinnae 18 to 26 pairs, 3.5 mm. long, 0.8 mm. broad, drying dark 

 green. Leaves of the flowering branchlets much smaller, with 2 to 4 

 porelike glands at the base of the rachis and occasionally a gland at 

 the apex; pinnae 2 to 5 pairs, consisting of 6 to 12 pairs of leaflets. 



Type in the herbarium of the Field Museum of Natural History, no. 

 58707, collected at the port of Silam (Tsilam), north coast of Yucatan, 

 April, 1895, by Dr. G. F. Gaumer (no. 1909). A second specimen from 

 the same locality is m the same museum, no. 36458, collected by Gaumer 

 (no. 655), apparently at the same time and from the same plant. Pho- 

 tographs and fragments of the type are in the U. S. National Herbarium. 



10. Acacia Donnelliana sp. nov. Closely related to the preceding, 

 but easil}' distinguished by its dark-colored polished spines and much 

 longer vegetative leaves. Flower heads globose, long-peduncled, borne 

 in clusters on special flowering branchlets very much as in A. globulifera, 

 but with relativeh' longer and more slender peduncles, the diameter of the 

 heads at anthesis 8 mm., length of longest peduncles 20 mm. Flowers 

 and interfloral bracteoles also much as in the latter species. Fruit not 

 observed. Large spines V-shaped, terete, 40 mm. long, sharply acumi- 

 nate, those of the type material blackish or dark mahogany-colored, 

 polished. Small spines subtendmg the flower clusters acicular, much like 

 those of A. globulifera, 5 to 7 mm. long. Vegetative leaves with 14 to 

 18 pairs of pinnae, these 42 to 52 mm. long, composed of 30 to 40 pairs of 

 approximate leaflets; leaflets linear-oblong, very unequal at the truncate 

 base, rounded or subacute at the apex, slightly curved, dark reddish or 

 bronze w^hen diy; leaf rachis 10 to 20 cm. long, puberulent, bearing 

 at its base 4 conoid nectar glands, each opening by a small elliptical pore 

 with a smooth reddish margin, and in addition to these a similar gland 

 at the base of each pair of pinnules. Leaves of flowering branches with 

 several pores at the base of the rachis and a pore at the base of each of 

 the 6 to 15 pairs of pinnae; these leaves sometimes rudimentary or even 

 lacking, in such cases the flower clusters subtended by a pair of small 

 V-shaped acicular spmes. 



