Compositae. 89 



CENTAU'REA SCABIO'SA {8i). Great Knapweed. 7—9- Bracts 

 (817) with ciliate margins, stem 2 — 3 ft. high grooved branched, heads 

 bright purple 13 — 2 in. diameter, florets of ray large scattered spread- 

 ing. Fields. 



Centau'rea calci'trapa (16). Stem 1—2 ft., leaves pinnatifid, involucral 

 (821) bracts ending in stiff spines | in. long, florets rose-purple. 



[W. L. 



y.^\\\.—BIDENS. 



Bracts of the involucre in two series — outer leafy spreading, heads discoid 

 yellowish, fruit compressed ribbed, pappus of 2 — 5 barbed bristles. 



BI'DENS TRI PARTITA {80). Bur-Marigold. 7—9. Leaves petio- 

 (756) late tri-cleft, heads only slightly drooping. Watery places. 



BI'DENS CER'NUA (81). 7—10. Leaves sessile oblong lanceolate 

 (755) serrate, heads drooping. Watery places. 



XIX. —^ UFA TORIUM. 



EUPATOR'IUM CANNABI'NUM (97). Hemp Agiimony. 7—9. 



(726) Heads discoid pale purple in dense terminal corymbs, florets 5 — 6, 

 bracts about 10 shorter than the flowers, pappus pilose rough, style- 

 arms long pubescent, leaves opposite downy 3 — 5 cleft, leaflets lanceo- 

 late deeply serrate. River banks and da?np woods. 



XX. — TANA CE TUM. 



TANACE'TUM VULGA'RE (102). Tansy. 8—9. Heads many in 



(770) corymbs dull yellow \ in. diameter, involucre hemispherical, outer 

 florets only longer than the bracts, leaves bi-pinnatifid, segments 

 deeply serrate. Waste places. 



XXI.— A F TEMISIA, 



Heads small discoid yellowish in racemes or panicles, florets few all 

 tubular, leaves alternate often much cut. 



ARTEMIS'IA VULGA'RIS (no). Mugwort. 7—9. Leaves pinna- 

 (772) tifid broad woolly beneath, heads erect. Waste places. 



ARTEMIS'IA ABSIN'THIUM (71). Wormwood. 7—9. Leaves 



(771) bi-pinnatifid silky, heads drooping. Aromatic. Waste places and in 

 gardens. 



XXII. —ANTENNARIA. 



ANTENNA'RIA DIOI'CA (84). Everlasting. 6—7. Heads small in 

 (741) corymbs dioecious, involucre imbricated inner bracts coloured white 



or pink, radical leaves spathulate woolly beneath, cauline leaves 



linear-lanceolate adpressed. Mountain pastures. 



