safford: myrmecophilous acacias 363 



lateral!}''; seed? in a single row. Spines more or less flattened and 

 broadened at the base, lunate or broadly subdeltoid. 



15. Acacia Nelsonii sp. nov. Plant with leaves much like those of 

 A. Colli nsii, but easily distinguished from that species by its light- 

 colored, broadly spreading, upcurved, more or less flattened stipular 

 spines, these about 4 cm. long, 10 mm. broad at base, sometimes lunate or 

 IjTe-shaped, smooth, pale olivaceous to tan-colored or buff, with reddish 

 browTi tips, becoming gray or whitish when dead. Small spines on 

 flowering branchlets 2 mm. long. Vegetative leaves with 4 to 8 pairs of 

 pinnae; rachis 7 to 12 cm. long, without interpinnal nectar glands but 

 with a row of 3 or 4 glands at the base; pinnae 4.5 to 5.5 cm. long, the 

 leaflets 14 to 19 pairs, uniformly brown when dry, linear-oblong, 8 to 

 10 mm. long, 2.8 mm. broad, those bearing apical bodies at length retuse 

 or truncate; rachis of pinnae sometimes with a minute solitary terminal 

 gland at the base of the uppermost pair of leaflets. Leaves of flowering 

 branchlets with 1 to 5 pairs of pinnae; rachis bearing at its base a row of 

 3 glands. Flower spikes 32 to 36 mm. long, including the peduncle, the 

 latter 11 to 13 mm. long, about equal in thickness to the axis of the 

 spike. Interfloral pedicelled bracteoles with orbicular peltate laminae, 

 these imbricated over the flowers before anthesis like the scales of a 

 fish, after anthesis their margins everted and concealed by the mass of 

 anthers. Flowers tubular-funnel form, obovoid, or broadly subcylin- 

 drical; calyx 1.2 to 1.3 mm. high, subentire or obtusely 4 or 5-lobed; 

 corolla one-fourth to one-third longer than the calyx, acutely 5 or 6- 

 lobed, the divisions sometimes irregularly cleft; stamens very numerous, 

 the filaments flesh-colored, the anthers straw-colored; style filiform. 

 Legumes small, 2-valved, at length dehiscent by ventral and dorsal 

 sutures, glabrous, dark bro-wn or blackish, compressed, nearly straight 

 along the dorsal suture, curved along the ventral suture, tapering at 

 the base and slightly retrocurved at the apex. Seeds ovoid or elliptical, 

 somewhat compressed but not flattened; testa hard, smooth, dark brown. 



Tj^pe in the U. S. National Herbarium, no. 399366, collected at Aca- 

 pulco. State of Guerrero, Mexico, April 30, 1903, by E. W. Nelson (no. 

 7024), with flowers and fruit. Cotype in the same herbarium, no. 

 692158, collected in the same locality, in 1895, by Dr. Edward Palmer 

 (no. 390a), without flowers and with a single legume. 



16. Acacia costaricensis Schenck, Repert. Nov. Sp. Fedde 12: 36 1> 

 1913.— Bot. Jahrb. Engler 50:465. 1914. 



Type in the Berlin Herbarium, collected near Lepanto, Costa Rica, in 

 Januarj^, 1857, by Dr. Carl Hoffmann (no. 275), without fruit. Speci- 

 mens collected by C. Wright in Nicaragua (U. S. North Pacific Explor. 

 Exped. 1853-56), cited by Schenck as conspecific, are in the Grisebach 

 Herbarium at Gottirigen, the Gray Herbarium, and the U. S. National 

 Herbarium (no, 692165), the last with broad flat pods terminating in a 

 sharp retrocurved point. 



17. Acacia penonomensis sp. nov. Closely related to Acacia costaric- 

 ensis, but with falcate pods, spikes of pale yellow flowers borne on very 



