162 PROCEEDINGS OF THE AMERICAN ACADEMY. 
obtusis vel rotundatis 6-20 mm. longis 5-14 mm. latis supra adpresse 
pilosis subtus sordide pubescentibus et minute albo-punctatis a_ basi 
rotundato nec cordato 5-nerviis petiolo 6-19 mm. longo tomentuloso; 
spicis brevibus axillaribus parte mascula perbrevi 1-3 mm. longa in 
pedunculo filiforme 6-9 mm. longo terminali; involucris foemineis 1-3 in 
basi pedunculi sessilibus 3-floris ad mediam partem 7-partitis; dentibus 
and often much exceeded by the peduncle which often bears below 1 to 3 
or more 9 involucres. 
+ Leaves tomentose. 
++ Indumentum of the stem non-glandular. 
= Terminal (chiefly 9 ) spike well developed 
8. A. seRICEA, Anderss. 
= = Pistillate involucres scattered chiefly at or near the base of lateral spikes: no 
well developed terminal spike. 
4. A vexuTina, Hook. f. 
++ ++ Indumentum of the stem glandular. 
5. A. STROBILIFERA, Hook. f. 
++ Leaves puberulent or pubescent. 
++ Terminal spike developed. 
= Involucres glandular-pubescent. 
6. A. renIFoRMIs, Hook. f. 
= = Involucres hirsute with long non-glandular as well as shorter glandular hairs. 
7. A. spicata, Anderss. 
++ No terminal spike. 
= Prostrate perennials branching from the base. 
a. Pistillate ta volaires 1 to 3, sessile at the very base of the rachis. 
1. Leaves about equalling the petioles, cordate, reniform. 
8. A. pirrusa, Anderss. 
2. Leaves about equalling me petioles, —— a at the base, obtuse 
rounded at the apex. 
9. A, ADAmMsIt, tiie: 
3. Leaves considerably shorter than the petioles, acutish. 
10. A. ALBEMARLENSIS, Robinson. 
b. Pistillate involucres borne somewhat above the base of the rachis. 
11. A. parvuta, Hook. f. 
= Erect annuals. 4 
a. Leaves cordate, 8 to 12 mm. long, obtuse or rounded: stem hirsute an 
glandular. 
12. A. corprrotta, Hook. f. 
b. Leaves 2 to 4 em. long, rhombic-ovate, subacute, somewhat narrowed to * 
y or not at all cordate base; stem glandular-puberulent. 
13. A. cHaTHAMeEnsts, Robinson. 
