The Collaborative International Dictionary
Periclinium
Periclinium \Per`i*clin"i*um\, n.; pl. Periclinia. [NL., fr. Gr. ? around + ? a bed.] (Bot.) The involucre which surrounds the common receptacle in composite flowers.
Wiktionary
periclinium
n. (context botany English) The involucre that surrounds the common receptacle in composite flowers.