S YS TEMA TIC B TANY. 63 



Class IX. Enneandria (nine stamens). — Laurel, Rheum 

 (rhubarb). 



Class X. Decandria (ten stamens). — Rhododendron, 

 Dianthus (pink), Ruta (rue), Cercis (Judas tree), Hydrangea, 

 Ceratopetalum (Christmas bush). 



Class XL Dodecandria (eleven to nineteen stamens). — 

 Reseda (mignonette), Sempervivum (house leek), Callicoma 

 (black wattle of New South Wales). 



Class XII. Icosandria (twenty or more stamens on the 

 calyx). — Rose, Cactus, Persica (peach), Eucalyptus (gum- 

 tree), Pyrus (apple). 



Class XIII. Polyandria (twenty stamens or more on the 

 receptacle). — Ranunculus (buttercup), Delphinium (lark- 

 spur), Papaver (poppy), Magnolia. 



Class XIV. Didynamia (four stamens — two long and two 

 short). — Verbena, Thymus (thyme), Digitalis (foxglove), 

 Lavandula (lavender), Antirrhinum (snap-dragon). 



Class XV. Tetradynamia (six stamens — four long and 

 two short). — Cheiranthus (wallflower), Brassica (cabbage), 

 Sinapis (turnip), Mathiola (stock), Raphanus (radish), Iberis 

 (candytuft). 



Class XVI. Monadelphia (stamens united at the base 

 into one bundle). — Passiflora (passion flower), Patersonia, 

 Malva (mallow), Hibiscus, Pelargonium. 



Class XVII. Diadelphia (stamens united into two 

 bundles). — Pisum (pea), Erythrina (coral-tree), Medicago 

 (lucerne), Trifolium (trefoil). 



Class XVIII. Polyadelphia (stamens united in many 

 bundles. — Citrus (orange and lemon), Tristania, Melaleuca 

 (paper-bark tree), Hypericum. 



Class XIX. Syngenesia (stamens united into a tube, and 



