CONTRIBUTIONS, NATIONAL HERBARIUM 35 



Volume 20 



Systematic studies of American plants. Pp. i-xv (title, advertisement, title page, note, 

 preface, contents, and illustrations) ; pp. 1-588 (parts 1-14) ; pp. 589-605 (index) ; 

 70 figs., 51 pis. 1917-1925. 



Part 



1. The Mexican and Central American species of Ficus. By Paul C, Standlcy. 



Pp. 1-35. May 31, 1917. 



2. The Middle American species of Lonchocarpus. By Henry Pittier. Pp. 37-93, 



43 figs., 6 pis. Aug. 3, 1917. 



3. New or noteworthy plants from Colombia and Central America — 7. By Henry 



Pittier. Pp. 95-132, 19 figs., 1 pi. June 18, 1917. 



4. The North American species of Aquilegia. By Edwin Blake Payson. Pp. 133-157, 



7 pis. Oct. 14, 1918. 



5. The allies of Selaginella rupestris in the southeastern United States. By G. P. 



Van Eseltine. Pp. 159-172, 8 figs., 8 pis. Oct. 1, 1918. 



6. Studies of tropical American phanerogams. By Paul C. Standley. Pp. 173-220. 



Aug. 29, 1919. 



7. The genus Homalium in America. By S. F. Blake. Pp. 221-235. Sept. 9, 1919. 

 New South American spermatophytes collected by H. M. Curran. By S. F. 



Blake. Pp. 237-245. Sept. 9, 1919. 



8. The North American species of Aster ella. By Alexander W. Evans. Pp. 247-312. 



Apr. 29, 1920. 



9. Scrophulariaceae of the central Rocky Mountain States. By Francis W. Pen- 



nell. Pp. 313-381. Apr. 29, 1920. 



10. Revision of the genus Acanthospermiim. By S. F. Blake. Pp. 383-392, 1 pi. 



June 20, 1921. 

 Revision of the genus Flourensia. By S. F. Blake. Pp. 393-409. June 20, 1921. 

 Revision of the genus Oyedaea. By S. F. Blake. Pp. 411-422. June 20, 1921. 

 Revision of the genus Tithonia. By S. F. Blake. Pp. 423-436. June 20, 1921. 



11. The identification of Berberis aqutfoUum and Berberis repens. By Charles V. 



Piper. Pp. 437-451, 3 pis. Jan. 26, 1922. 



12. New or noteworthy plants from Colombia and Central America — 8. By Henry 



Pittier. Pp. 453-490, 4 pis. Jan. 9, 1922. 

 13 Revision of the American species of Rinorea. By S. F. Blake. Pp. 491-518, 7 pis. 

 July 19, 1924. 

 New plants from Venezuela. By S. F. Blake. Pp. 519-541, 10 pis. July 19, 1924. 

 Hemibaccharis, a new genus of Baccharidinae. By S. F. Blake. Pp. 543-554, 

 4 pis. July 19, 1924. 

 14. The American species of Canavalia and Wenderothia. By C. V. Piper. Pp. 

 555-588. Apr. 27, 1925. 



Volume 21 



Flora of the District of Columbia and vicinity. By A. S. Hitchcock and Paul C. 

 Standley. Pp. 1-329, 1 fig., 42 pis. 1919. 



Volume 22 



Systematic plant studies, chiefly tropical American. Pp. i-xlv (title, advertisement, 

 title page, note, preface, contents, and illustrations) ; pp. 1-748 (parts 1-10) ; 

 pp. 749-777 (index) ; 87 figs., 64 pis. 1920-1927. 



Part 



1. Revisions of North American grasses: The North American species of 



Ichnanthus. By A. S. Hitchcock. Pp. 1-12, 9 pis.; The North American 

 species of Lasiacis. By A. S. Hitchcock. Pp. 13-31, 15 pis.; The North 

 American species of Brachiaria. By Agnes Chase. Pp. 33-43, 6 figs.; The 

 North American species of Cenchrus. By Agnes Chase. Pp. 45-77, 14 figs. 

 Mar. 29, 1920. 



2. A study of Allocarya. By Charles V. Piper. Pp. 79-113. Mar. 13, 1920. 



S. Revisions of North American grasses: The North American species of Isachne. 

 By A. S. Hitchcock. Pp. 115-121, 8 pis.; The North American species of 



