alpine armour armoured Asteraceae Carlina acaulis carline dicotyledon Eberwurz edible europe flowering fortune Good humidity hunter's bread hurt indicator medicine needles perennial plant rosette silver thistle spine spiny star stemless sun thistle thorn thorny traditional antenna Argynnis Argynnis paphia butterfly England feed feeding flower fritillary haustellum insect Lepidoptera nature proboscis rest resting rhopalocera silver-washed fritillary suck sucking summer Sussex wing