DICOTYLEDONOUS PLANTS 161 



VI. THASPIUM, Nutt. 



Perennial herbs. Stem erect. Leaves 1-2, compound in 

 threes. Umbels compound, involucre and involucels usually 

 wanting. Elowers yellow or purple. Calyx-teeth small, 

 acute. Pruit ovoid or oblong, somewhat laterally compressed ; 

 carpels smooth, strongly ribbed, oil-tubes between the ribs.* 



1. T. barbinode, Nutt. Hairy Meadow Parsnip. Stem erect, 

 branching above, downy at the nodes, 2-7 ft. high. Leaves petioled, 

 slightly downy, leaflets mostly thin, ovate, toothed, incised or lobed 

 toward the apex, entire toward the base. Umbels long-peduncled, 

 few-rayed. Fruit oblong, lateral and central ribs strongly winged. 

 Along streams.* 



Vn. ZIZIA, Koch. 



Smooth perennials. Leaves generally as in Thaspium. 

 Involucre wanting ; involucels of small bractlets. Umbels 

 compound. Flowers yellow. Calyx-teeth prominent. Eruit 

 more or less ovoid, smooth, with thread-like ribs, oil-tubes 

 large and solitary between the ribs and a little one in each 

 rib ; the central fruit of each umbellet sessile. 



1. Z. aurea, Koch. Meadow Parsnip, Golden Alexanders. 

 Smooth, stem erect, 1-2 ft. high. Root-leaves mostly heart-shaped 

 and serrate, stem-leaves usually once compound in threes. Flowers 

 deep yellow. Fruit between globose and ovoid, about ^ in. long, aU 

 the ribs generally winged. Woods and thickets. 



vra. pastinaca, l. 



A tall, smooth biennial with a stout, grooved stem. Leaves 

 pinnate. Flowers yellow, in large umbels, with hardly any 

 involucre. Calyx-teeth wanting. Fruit oval, very flat, with 

 a thin wing, oil-tubes single, running the whole length. 



1. P. sativa, L. Common Parsnip. Cultivated from Eiirope 

 for its large, conical, sweet, and edible roots. Also introduced in 

 waste places. 



IX. HERACLEUM, L. 



A stout perennial, with the very large leaves compound in 

 threes. Umbels large, compound, with the involucels many- 



