April, 1916. Alack an Reef — Millspaugh 429 



From its association on these cays I judge that the fruits are aquavec- 

 tent. Its growth in no wise gives the appearance of bird transportation. 



9. Flaveria linearis Lag. Gen. et Sp. Nov. S3- 



A few plants of this species were found near the coral cairn on Perez 

 Island. A few more were found scattered in the Sesuviimi carpet a short 

 distance northwestward from the cairn. The species is fairly common 

 on the coast of the mainland of Yucatan and on the island of Cozimiel. 



This dispersion of this species to the Alacran Reef must have been 

 intestinally avevectent as the seeds have no coma and the position of 

 the plants on Perez savors highly of resting birds. 



10. Portulaca oleracea Linn. Sp. PI. 445. 



A few individuals of this species were found scattered amongst 

 the Sesuvium of Perez and Pajaros cays. It had not yet become im- 

 planted on the other cays visited. 



In my studies of the intimate dispersion of species upon sand islets* 

 I have fovmd this species only upon inhabited islands and then generally 

 in areas that were at the time, or had been, more or less cultivated for 

 some purpose. The position of the plants on Perez and Pajaros in 

 no way indicate homovectence, though on Perez this might have been 

 possible. The dispersional indications in regard to this species are not 

 sufficiently plain to me at this time to permit a distinct statement. 



11. Cyperus brunneus Sw. Fl. Ind. Occ. 1:116. 



One clump only of this species was found on the cays that on the 

 southwest end of Perez Island just beyond the Sporobolus colony. 



This species is quite a common element of the Antillean strand flora 

 from the Bahamian Archipelago through to Vera Cruz, Mexico. It 

 occurs in places all along the Yucatan coast and on the strands of the 

 island of Mugeres. 



The seeds are avevectent per pedis et intestinis. 



12. Atriplex cristata H. & B. ex Willd. Sp. PI. 4:959. 



A group of a few individuals of this species was found in the Sporobol- 

 us colony on the south end of Perez and qmte a large cluster in the same 

 association on Chica. On Pajaros a small group was found in associa- 

 tion with the Sesuviimi. The species has also been returned from the 

 Yucatan main coast at Progreso and Silam. 



I judge that the fruits are 'avevectent, being transported on the 

 webbed feet of the booby, and that the cliunp in the Sesuvitmi of Pajaros 

 came originally from the older implantation on Chica. 



*" Flora of the Sand Keys of Florida," Field Museum of Natural History, Botany, 

 Vol. 2, no. 5. 



