FLORA OF THE GALAPAGOS ISLANDS. 241 



tween the flora of the Galapagos group and that of Cocos Island. The 

 latter is situated about three-sevenths of the way from the coast of Costa 

 Rica to the Galapagos Archipelago. Until very recently the flora of 

 Cocos Island has been scarcely known at all. Largely through the 

 efforts of Professor H. Pittier and Messrs. Snodgrass & Heller, about 

 eighty plants have now been secured on the island, and of these only 

 the following eighteen are common to the flora of the Galapagos group : 



Plagiochila Anderssonii Paspalum conjugatum 



Acrostichum aureum Paspalum distichura 



Asplenium rhizophyllum Caesalpinia Bonducella 



Nephrolepis acuta Euphorbia pilulifera 



Polypodium aureura Ricinus communis 



Polypodium lanceolatum Hibiscus tileaceus 



Polypodium Phyllitidis Ipomoea biloba 



Eleusine indica Ipomoea Bona-nox. 

 Panicum sanguinale 



It will be noticed that with the exception of the hepatic (Plagiochila 

 Anderssonii) all of these species are weeds or plants of wide tropical 

 distribution. 



Composition of the Flora. 



As with most insular floras, the vegetation of the Galapagos Islands is 

 striking rather by the absence of certain great groups than by the 

 number and diversity of the genera and families represented. For in- 

 stance, in the pteridophytes there is a total lack of arborescent forms on 

 the one hand and of the filmy ferns ( Trichomanes, Hymenophyllum, etc.) 

 on the other. There are no gymnosperms ; and among the monocotyle- 

 dons there are no palms, aroids, rushes, or Liliaceae. Indeed, if we 

 except the grasses and sedges (both well represented), the monocotyledons 

 are shown only by some half-dozen scattered species. Among the di- 

 cotyledons the families best represented are the Amarantaceae, JSfyctagi- 

 naceae^ Aizoaceae, Leguminosae (about 10 per cent of the phanerogamic 

 vegetation), Euphorbiaceae (about 12 per cent), Malvaceae, Cactaceae, 

 Convolvulaceae, Boraginaceae, Verhenaceae, Lahiatae, Solanaceae, 

 Ruhiaceae, and Cornpositae (about 13.5 per cent). Several great dicoty- 

 ledonous families, widely distributed and abundant in the tropics of 

 continental America, such as the Sapindaceae, Myrtaceae, Melastomaceae, 

 Lythraceae, and Onagraceae, are scarcely or not at all represented in the 



VOL. XXXVIII. — 16 



