822 PATAGONIAN EXPEDITIONS I BOTANY. 



3. XANTHIUM SPINOSUM Linn. 



Strong, 3-partite spines at the base of the leaves, which are 3-lobate, 

 minutely puberulous above, hoary along the nerves and underneath. 

 Seines yellow, 25 mm. long. 



(Eur. and N. Amer.); N. Patagon. ; the roasted fruits are used for 

 making a drink like coffee. 



36. ECLIPTA Linn. 



Branching herbs, with opposite leaves and small peduncled, terminal 

 and axillary heads of tubular and radiate, whitish flowers. Involucre 

 broad, its scales usually 2-seriate, herbaceous. Receptacle with awn-like 

 chaff subtending the achenes. Ray-flowers fertile ; disk flowers perfect, 

 mostly fertile, and mostly 4-toothed. Style-branches obtuse or with tri- 

 angular tips. Achenes thick, with rough sides. Pappus none, or a few 

 teeth. 



Species 4, chiefly tropical. 



E. ALBA Hassk. 



Rough annual, 60 cm. high. Leaves nearly lanceolate, denticulate or 

 entire, narrowed to a sessile base, or some petioled. Rays short. 

 Achenes 4-toothed. 



(Fig. in Eng. & Prantl, iv, 5, p. 227, E-H.) 



(Trop. Amer., naturalized in U. S.) ; N. Patagon., by Rio Negro. 



37. WEDELIA Jacq. 



Rough herbs or undershrubs, with opposite leaves and mediocre heads, 

 pediceled at the ends of branches or axillary. Flowers yellow, radiate, 

 all usually fertile. Involucral scales 2-seriate, the outer green. Chaff 

 embracing the flowers. Anthers basi-entire or sagittate. Style-branches 

 with acute appendages. Achenes thick, laterally compressed, or in the 

 ray triquetrous ; glabrous or hairy or tubercled. Pappus mostly cup-like 

 or with caducous awns. (Fig. in Eng. & Prantl, iv, 5, p. 230, A.) 



Species 60, in warm climates. 



W. BUPHTHALMIFLORA Ltz. 



Many erect stems from the woody root; branching decussately or 

 sparsely, with gray cortex, 50 cm. high. Leaves narrow, lanceolate, 



