ROBINSON.— DIAGNOSES ETC. OF SPERMATOPHYTES. 507 
D. aurantia (L.), comb. nov. Aster aurantius L. Sp. Pl. i. 877 
(1753). Aster americanus, foliis pinnatis, etc., Rel. Houst. 7, t. 1 
(1781). Dysodia appendiculata Lag. Nov. Gen. et Spec. 29 (1816). 
Clomenocoma aurantia (L.) Cass. Dict. Sci. Nat. ix. 416 (1817), lix. 
66 (1829). Clappia awrantiaca Benth. in Hook. Ie. xii. t. 1104 (1872). 
D. aurantiaca (Brandegee), comb. nov. Hymenatherum aurantia- 
cum Brandegee, Zoe, v. 258 (1908). 
D. pentachaeta (DC.), comb. nov. Hymenatherum Berlandieri 
DC. Prod. v. 642 (1836). H. pentachaetum DC. 1. ¢.; Gray, Proce. 
Am. Acad. xix. 42 (1883), where the two species of DeCandolle are 
united under the name of the latter from the standpoint of priority of 
position. . Thymophylla pentachaeta (DC.) Small, Fl. S. E. U. S. 
1295, 1341 (1903). In making the transfer to Dyssodia the author 
would have preferred to reinstate the first name employed by DeCan- 
dolle, but this is forbidden by Art. 46 of the International Rules, 
which reads, “‘ When two or more groups of the same nature are united, 
the name of the oldest is retained. If the names are of the same date, 
the author chooses, and his choice cannot be modified by subsequent 
authors.” In the case in hand, the two names Berlandieri and 
pentachaetum were of the same date. The species seem first to have 
been united by Gray, who chose the second of the two names, and this, 
of course, is decisive according to the article just quoted. 
_D. concinna (Gray), comb. nov. Hymenatherum concinnum 
Gray, Syn. Fl. i. pt. 2, 446 (1884). 
D. diffusa (Gray), comb. nov. Hymenatherum diffusum Gray, 
Pl. Wright. i. 116 (1852). 
D. Greggii (Gray), comb. nov. Thymophylla Greggii Gray, Pl. 
Fendl. 92 (1849). Thymophyllum Greggiti (Gray) Hemsl. Biol. Cent.- 
Am. Bot. ii. 221 (1881). Hymenatherum Greggit Gray, Proc. Am. 
Acad. xix. 42 (1883). 
D. Hartwegi (Gray), comb. nov. Hymenatherum Berlandieri 
Benth. Pl. Hartw. 18 (1839), by error of determination, not DC. 
H. Hartwegi Gray, Pl. Wright. i. 117 (1852). , 
D. Neaei (DC.), comb. nov. Hymenatherum ? Neaei DC. Prod. v. 
642 (1836). H. boeberoides Gray, Pl. Wright. i. 115 (1852). H. 
Naei Hemsl. Biol. Cent.-Am. Bot. ii. 220 (1881); Gray, Proc. Am. 
Acad. xix. 41 (1883). 
‘ D. neo-mexicana (Gray), comb. nov. Adenophyllum Wrightit 
ray, Pl. Wright. ii. 92 (1853). Hymenatherum neo-mexicanum Gray, 
Seeing Acad. xix. 40 (1883), not H. Wrightii Gray, Pl. Fendl. 89 
