308 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
Within a group of plants that may be taken as a species; the same is true of 
the size of the flowers. The color of the flowers is more or less variable, white- 
flowered forms of normally red-tlowered species being occasionally found. The 
fruit is perhaps of the most importance. The outer and inner fruits in a single 
head are often very different in form: but the inver ones in different heads on 
the same plant are remarkably uniform in shape. A word may be necessary 
in explanation of the terms ‘“ turbinate” and “ biturbinate,” as employed by 
Doctor Rydberg, whose usage I have followed. The distinction between the two 
is difficult to understand from mere descriptions, but | hope that by reference 
to the accompanying drawings it may be more easily grasped. 
KEY TO THE GROUPS, 
lowers yellow-_-------- 1. LATIFOLIAR, 
Flowers red or white, never vellow. 
Flowers dark, deep red; fruit large and with very thick 
wings_ ee sos TL. MARITIMAR, 
Flowers lighter, purplish red or white: fruit smaller and 
with thinner wings. 
Low perennials which are almost acaulescent, with 
a short and thick caudex ----- _ IV. NANAR, 
Annuals or perennials with loug stems which have 
conspicuous internodes, 
Involucral bracts small, usually not scarious, 
Inostly narrow. 
Central cavity of the fruit extending quite 
to the edges of the wings when wings 
are present ooo V. 'TURRINA'TAE, 
Central cavity of the fruit not extending 
quite to the edges of the wings ____ _. TL. UMBELLATAR. 
Involucral bracts usually much larger, scarious, 
mostly broad ~~ VI. FRAGRANTES, 
KEY TO THE SPECIES BY GROUPS. 
I. LATIFOLIAR. Prostrate perennials with thick, fleshy roots, 
and thick, orbicular leaves; fruit) coriaceous, large, with 
4 or 5 thick wings which are widest in the middle and nar- 
rowed above and below. A single species_-... 1. A latifolia. 
II. MAkiITIMAK. Prostrate perennials; fruit coriaceous, 
large, with 4 or 5 thick wings, the central ‘avity extend- 
ing almost or quite to the edges of the wit gs; bracts thick, 
narrowly elliptical. A single species_____ ~e ee 2. A. maritima, 
TH. UMBELLATAR. Prostrate annuals or perennials; flowers 
red (white in one species) ; bracts mostly lanceolate, small: 
fruit with thin or rarely somewhat thickened wings, the cen- 
tral cavity not extending quite to the edges of the wings. 
Fruit not winged; plant very small; leaves orbicular: only 3 
or 4 flowers in each head _---- V7. A. alpina, 
Fruit winged. ‘ 
Stems puberulent or glabrous, not villous. 
Wings thickened and coriaceous. 
Stems almost glabrous, internodes long, flowers 
red__--- _. 8. A. insularis, 
Stems puberulent, internodes short, flowers 
white_---- ee at. 
