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-puuctatis a basi 

 rotuudato iiec cordato 5-nerviis petiolo 6—19 mm. longo tomeutuloso; 

 spicis brevibus axillaribus parte mascula perbrevi 1-3 mm. louga ia 

 pedimculo filiforme 6-9 ram. longo terminali; iiivolucris foemineis 1-3 in 

 basi peduuculi sessilibus 3-floris ad mediam partem 7-partitis; dentibus 



and often much exceeded by the peduncle whicli often bears below 1 to 3 

 or more J involucres. 



•I- Leaves tomentose. 



t-f Indumentum of the stem non-glandular. 



= Terminal (chiefly ^ ) spike well developed. 



3. A. SERICEA, Anderss. 



= = Pistillate involucres scattered chiefly at or near the base of lateral spikes : no 



well developed terminal spike. 



4. A TELUTINA, Hook. f. 



++ -w- Indumentum of the stem glandular. 



5. A. STROBILIFEEA, Hook. f. 



-1--I- Leaves puberulent or pubescent. 



•*-+ Terminal spike developed. 



= Involucres glandular-pubescent. 



6. A. RENIFORMIS, Hook. f. 



— = Involucres hirsute witii long non-glandular as well as shorter glandular hairs. 



7. A. spiCATA, Anderss. 



•M- ++ No terminal spike. 



= Prostrate perennials branching from the base. 



a. Pistillate involucres 1 to 3, sessile at tlie very base of tiie rachis. 



1. Leaves about equalling the petioles, cordate, reniform. 



8. A. DIFFUSA, Anderss. 



2. Leaves about equalling the petioles, suborbicular, rounded at the base, obtuse 



or rounded at the apex. 



9. A. Adamsii, Robinson. 



3. Leaves considerably shorter than the petioles, acutish. 



10. A. ALBEMARLENSIS, EobinSOU. 



h. Pistillate involucres borne somewhat above the base of the rachis. 



11. A. PARVULA, Hook. f. 



= = Erect annuals. 

 a. Leaves cordate, 8 to 12 mm. long, obtuse or rounded: stem hirsute and 



glandular. 



12. A. coRDiFOLiA, Hook. f. 



h. Leaves 2 to 4 cm. long, rhombic-ovate, subacute, somewhat narrowed to a 

 scarcely or not at all cordate base; stem glandular-puberulent. 



13. A. CHATHAMENSis, KobinsoH. 



