HAY-SCENTED FERN. 



monly there is but one fruit-dot to a lobe, but sometimes 

 there are two on the upper side, and rarely a third on the 

 lower. The involucre is like a little cup, and is formed partly 

 from the reflexed tip of the fertile tooth or lobule, and partly 

 of a special true involucre, which meets the other part and is 

 united with it. Inside the cup are found about a dozen spo- 

 rangia, which have from twenty to twenty-four articulations 

 in the ring. The spores are trigonous with somewhat im- 

 pressed sides, and three faint vittse along the angles. 



There has been a great deal of confusion respecting the 

 names of this fern, both generic and specific. The genus 

 Dicksonia was proposed by L'Heritier in 1788 for two species, 

 D. Culcita of the Azores and Madeira, and D. arborescens of 

 St. Helena. In these the involucre is very distinctly two- 

 valved, the outer valve formed from the apex of a lobe. About 

 a dozen other species are now known, which are plainly con- 

 geners of these two. In 1801, Bernhardi proposed a genus 

 Dennstcsdtia for the Trichomanes flaccidum of Forster, a fern 

 much more like our own, and, like it, having a cup-like, and 

 not two-valved, involucre. But the proposed genus was 

 promptly rejected by Swartz, Schkuhr and Willdenow, and 

 the plant referred to Dicksonia, which by 18 10 was made 

 the recipient of as many as twenty species. Since then Sit- 

 obolium (or Sitolobium), Patania and Adectum have been 

 proposed for some of these species with cup-like involucres. 

 Some of these names have met with a limited acceptance, 

 but all were rejected by Hooker. The authors of Species 



