8 Contributions from the Gray Herbarium 
species with much the same narrow leaves as those which distin- 
guish H. angustifolium, a somewhat similar involucre, and the 
same prominent crustaceous carpopod (see p. 31, footnote) to the 
achene.! 
The monotypic genus Haplocalymma Blake, known at present 
only by two collections from Morelos, with its pappus like that of 
Hymenostephium and its uniseriate involucre, is clearly a lateral 
offshoot of the Diplostichis-Hymenostephium line, its prominent 
character of involucre being one shared by only a very few of the 
Verbesininae, those which have it being genera of comparatively 
remote relationship, while the nature of the phyllaries is rather 
more suggestive of some species of the section Diplostichis of 
Viguiera than of Hymenostephium. 
There remain for consideration the relationships of Helianthus 
and Tithonia to Viguiera, as well as those of the species of Gymno- 
lomia to the other groups here considered. Tithonia Desf., as now 
generally accepted, includes about eight species of Mexico and Cen- 
tral America, one or two of which have become somewhat widely 
naturalized. All are apparently annuals, with the exception of a 
single strongly woody species, and are chiefly distinguished from 
Viguiera, of which they have the persistent pappus of awns and 
squamellae, by the strongly swollen and fistulose fruiting peduncle. 
Additional characters of some significance are the broad normally 
three-lobed leaves, unknown in Viguiera or Helianthus, and the 
stiff abruptly acuminate pales of the receptacle, which in fruit 
* The following species of Gymnolomia require transfer to Hymenostephium: 
HYMENOSTEPHIUM microcephalum (Less.),comb. nov. — akg es lomia micro- 
cephala Less. Linnaea he srg (1830); Greenm. Proc . Acad. xxxix. 1s 
pina sr one & Greenm. ae comb. nov. — Gymnolomia patens var. 
guairanldaaa Teoh & Race fa pt Nat. Hist. xxix. ~ age Mack 
brethepoie Rob. ry Gree 1. on OE pw mece te (Rob. & G 
G - Field Col. Mus. = il. 347 (1912). ~ i sisllen Blake (1915) is 
only varietally rar 
- CoRDATUM (H. & A.) Blake, Journ. Bot. liii. 268 (1915). — Gymnolomia 
costaricensis Benth. (1852), of which G. patens Gray (1861-62) is the most 
important synonym, is not specifical separable. — The departures from cur- 
rent usage indicated by the s nonymy given under tes three above species will 
receive due elaboration niet explanation elsewher 
(Klatt), comb. nov. — Gym nolomia Goobelit Klatt in Goebel, 
Pflanzenbi ol. vgn one ii. 49 (1891); Rob. & Greenm. Proc. Bost. Soc. Nat. 
