▁to ▁ ∼ 7 6 – 6 6 ▁My a ▁( C amp an ian ▁to ▁Ma astr icht ian ) ▁and ▁assigned ▁to ▁the ▁ext ant ▁genus ▁Das y phy ll um . ▁Bar red a , ▁et ▁al . ▁( 2 0 1 5 ) ▁estimated ▁that ▁the ▁crown ▁group ▁of ▁A ster aceae ▁evol ved ▁at ▁least ▁ 8 5 . 9 ▁My a ▁( L ate ▁C ret ace ous , ▁Sant onian ) ▁with ▁a ▁stem ▁node ▁age ▁of ▁ 8 8 - 8 9 ▁My a ▁( L ate ▁C ret ace ous , ▁Con ia cian ). ▁ ▁It ▁is ▁still ▁unknown ▁whether ▁the ▁precise ▁cause ▁of ▁their ▁great ▁success ▁was ▁the ▁development ▁of ▁the ▁highly ▁special ised ▁capit ul um , ▁their ▁ability ▁to ▁store ▁energy ▁as ▁f ruct ans ▁( main ly ▁in ul in ), ▁which ▁is ▁an ▁advantage ▁in ▁relatively ▁dry ▁zones , ▁or ▁some ▁combination ▁of ▁these ▁and ▁possibly ▁other ▁factors . ▁ ▁E col ogy ▁▁ ▁A ster ace ans ▁are ▁especially ▁common ▁in ▁open ▁and ▁dry ▁environments . ▁ ▁Many ▁members ▁of ▁A ster aceae ▁are ▁pol lin ated ▁by ▁insect s , ▁which ▁explains ▁their ▁value ▁in ▁attract ing ▁benef icial ▁insect s , ▁but ▁an em oph ily ▁is ▁also ▁present ▁( e . g . ▁Amb ros ia , ▁Ar tem is ia ). ▁There ▁are ▁many ▁ap om ict ic ▁species ▁in ▁the ▁family . ▁ ▁Se eds ▁are ▁ordin arily ▁dispers ed ▁int act