162 PROCEEDINGS OP 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 

 rotuudato nee cordato 5-nerviis petiolo 6-19 mm. longo tomentuloso; 

 spicis brevibus axillaribus parte maseula perbrevi 1-3 mm. longa in 

 pedunculo filiforme 6-9 mm. longo terminali; involucris foemineis 1-3 in 

 basi peduueuli 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. 



3. A. sericea, Anderss. 



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



well developed terminal spike. 



4. A velutina, Hook. f. 



++ ++ Indumentum of the stem glandular. 



5. A. STROBIL1FERA, Hook. f. 



■*-■*- Leaves puberulent or pubescent. 



■w 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 involucres 1 to 3, sessile at the very base of the 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. albemari.ensis, Robinson. 



b. 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. 



b. 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. chathamexsis, Robinson. 



