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THE GENUS OLEANDRA. 



By Willard N. Clute 



As relationships go in the fern world, a few families 

 contain a majority of the species. Such genera as Poly- 

 podium, Pteris, Asplenium,' Trichomanes, and Nephr od- 

 ium, represented in our region by from one to half a 

 dozen species, in other climes include many hundreds. 

 Clustered about these great genera are various smaller 

 ones which resemble the leaders in many particulars, but 

 differ enough to have generic names of their own. Re- 

 lated to Pteris we find Pellcea, Cheilanthes, Adiantum, and 

 others whose species often so closely resemble that genus 

 that they are mistaken for members of it. Similarly 

 about Nephr odium , we find Aspidium, Sagenia, Poly- 

 stichum, Nephrolepis and the subject of this note. Like 

 its near ally, Nephrolepis, the genus Oleandra is what is 

 called a " natural genus," that is, the species are all so 

 much alike that they would be recognized as members of 

 the genus whether found in fruit or not. Except for this 

 peculiarity of habit, there is little to warrant their separa- 

 tion from Nephr odium. The sori and indusia are practi- 

 cally alike and fixed to the fronds in the same manner, 

 thought their location on the fronds is quite character- 

 istic. In all the species the fruit-dots are found in a 

 single or double row not far from the midrib and parallel 

 to it, as shown in our illustration. The rootstock is 

 usually scandent or creeping, and covered with silky 

 scales. Along this rootstock at intervals the fronds ap- 

 pear, being jointed to it by an articulation near the base 

 of the stipes. 



There are about half a dozen species of Oleandra in the 

 world, but these are widely distributed. There are two 

 in the American tropics, one in India, one in Africa, and 

 two in Ceylon, Assam, and the East Indies. The species 

 figured is O. JVallichii, from Northern India, collected by 

 C. W. Hope, author of a work on the ferns of that region. 



