MEXICAN AND CENTRAL AMERICAN UMBELLIFER^ II7 



Fruit with obscure ribs. 



Fruit somewhat scabrous.. ..22. Ammoselinum. 

 Fruit smooth. 



Involucre and invoUicels conspicuous. 

 215. Berula. 

 Involucre and involucels not conspicuous (in 



the native species) 24. Pimpinella. 



Fruit flattened dorsally. 

 Seed-face sulcata. 



Stylopodium obsolete 32. Prionosciadium. 



Stylopodium conical 34. Deanea. 



Seed-face plane. 



Fruit linear or oblanceolate in outline ; Guatemalan. 



Fruit linear; arborescent 37. IMyrrhidendron. 



Fruit oblanceolate; perennial herbs. 



35. Enantiophylla. 

 Fruit orbicular or nearly so. 

 Stylopodium low conical. 



Dorsal and intermediate ribs filiform. 



33. Rhodosciadium. 

 Dorsal and intermediate ribs prominent. 



Leaves with rather large ovate or lanceolate seg- 

 ments 31. A 7igelica . 



Leaves with small segments.. 30. Conioselinuni. 

 Stylopodium obsolete 38. Pejicedanum. 



I. HYDROCOTYLE L. Sp. PI. i: 234. 1753. 



The genus has a world-wide distribution, and in Hemsley's cata- 

 logue eight species, seven of which are named, are enumerated as oc- 

 curring in the Mexican and Central American region, as follows: 

 II. bonplandi ^ich..^ H. bonariensis\u?i.\n.^ H. interrtipta ^iuh]., H. 

 mexicana Cham. & Schlecht., H. prolifera Kellogg, H. pus ilia Rich., 

 and H. raminculoides L. Some of these are perhaps to be excluded, 

 and H. 2i77ibellata and probably other species are to be added. Of 

 these H. mexicana is the only endemic species. 



Hydrocotyle bonariensis Lam. Encycl. 3 : 153. 1789. 



Tamaulipas : sand dunes at Tampico, Pritigle 63=^9; Alta Mira, 



E. A. Goldma7i 94, April 20, 1898. 

 Oaxaca : Tehuantepec City, altitude 45 meters, Nelson 2620, May 

 29, 1895. 



Hydrocotyle mexicana Cham. & Schlecht. Linnnsa 5: 208. 1830. 

 Chiapas: about Tumbala, altitude 1 200-1650 meters. Nelson 3301, 



October 20-29, ^%5* 

 Guatemala: near Nenton, altitude 900-1200 meters. Nelson t^Szt^, 

 December 13, 1895; Volcano Santa Maria, altitude 2400-3450 

 meters. Nelson 3702, January 24, 1896. 



