APPENDIX 



517 



Fig. 4. Head of yarrow 



J, top view (magnified); B, lengtliwise section (magnified), re, receptacle; i, 



involucre; ;■, ray flowers; il, disk flowers; c, corolla; s, stigma; ch, chaff oi 



bracts of receptacle 





A B 



Fig. 5. -1. panicle of oat; B, compound umbel of carrot 



