APRIL, 1919. XANTHIUM MILLSPAUGH AND SHERFF. 49 



The two are well connected, furthermore, by the various other specimens 

 of differing stages of maturity examined by us and cited above. 



21. XANTHIUM CAMPESTRE Greene, Pittonia 4: 61. 1899. 



Caulis saepe lineis purpureis brevibus maculatus, supra scabridus, 

 5-8 dm. altus. Folia subcrassa, subdeltoidea, dentata aut serrata, non 

 perspicue lobata, ad basim truncata aut cordata, supra scabra, infra 

 scabro-pubescentia, petiolis adjectis 6-17 cm. longa, petiolis laminis 

 subaequantibus. Fructus (PI. VII, f. 21; PI. X, ff. 7-8) maximi, maxi- 

 mam partem singulatim dispositi, ovoideo-conici; corpore non saepe 

 aspectabili sed aculeis plerumque numerosis et densissimis armato, 

 demum circ. 2.3-2.6 cm. longo et 1-1.3 cm. crasso; rostris late diver- 

 gentibus, infra crassis et pubescentibus, supra glabratis et tenuiter 

 hamosis, 6-7 mm. longis; aculeis teretibus, arcuatis, infra (demum 

 ferrugineo-) hispidissimis, supra glabris et ad apicem hamosis, circum 

 5 mm. longis; toto fructu (aculeis et rostris adjectis) demum 2.8-3.5 cm - 

 longo et 2-2.5 cm - lato. 



DISTRIBUTION: California. 



SPECIMENS EXAMINED: CALIFORNIA: Chico, June 27, 1890, Edward 

 L. Greene (Hb. Greene 19837; type); Chico-Hamilton Road, 9.5 km. 

 northwest of Chico, A. A. Heller 11629 (Hb. Calif. 179073; Hb. Field 

 426983; Hb. Gray; Hb. Greene 51204; Hb. Mo. 748145; Hb. N. Y., a 

 more mature specimen, with the burs just turning reddish in color.) 



This species is distinguished from most others by the great size of its 

 burs, these coming to have, when well-developed, an expanse (including 

 the beaks and prickles) of about 3.5 cm. in length and 2.5 cm. in width. 

 In Greene's type specimen, the prickles are remote enough to permit a 

 view of the body of the bur. The several somewhat immature speci- 

 mens by Heller have the prickles more densely grouped together, leav- 

 ing the body mostly concealed. The burs have a decidedly yellowish- 

 green color until nearly mature, when they turn to a reddish color, 

 rather closely resembling those of X. oviforme Wallr. 



