226 Dr. Greville on a new species of Dawsonia. 



Jan. 1846. The temperature of this raonth was higher by 3° 

 than that of January in any of the many years referred to. 



Feb. 1846. The temperature was as high in Februaiy 1827 

 as in this month, and was within 1° of being as high in 1826 

 and 1829. 



The chief feature of the winter was therefore in the high tem- 

 perature of the month of January, and again, of that and February 

 combined; the difference between the mean of the two months 

 being less than 1°. A check to the rapidly advancing vegetation 

 was given on the 18th of March, upon the night of which and 

 the following, the thermometer at the Botanic Garden, Belfast, 

 fell to 21° Fahrenheit. 



XXVII. — Notice of a new species of Dawsonia. By Robert 

 Kaye Greville, LL.D., F.R.S.E., F.L.S. &c.* 



[With a Plate.] 

 No one can take the most cursory glance at the subject of the 

 present notice without being satisfied that it is distinct from the 

 only other described species, Dawsonia polytrichioides of Hooker ; 

 and yet it is extremely difficult to draw up such a character as 

 shall distinguish it on paper, if we except the much larger size. 

 The latter feature however is so decided, that practically there can 

 be no hesitation in pronouncing between the two species. 



The single specimen which I possess of the new species, which 

 I propose to name Dawsonia superha^ was sent to me from Au- 

 stralia a few years ago by my friend Augustus Erskine, Esq., 

 Deputy-Assistant Commissary-General in that country. 



In the same parcel were some New Zealand plants, but from 

 those with which the Dawsonia was associated in the collection, I 

 have little doubt that it, as well as the previously known species, 

 is an Australian plant. My specimen is fully fourteen inches 

 high, whereas the tallest of those of D. polytrichioides, as de- 

 scribed both by Dr. Robert Brown and Sir W. J. Hooker, do not 

 exceed four inches, including the seta. The leaves are an inch 

 in length (nearly three times longer than in D. polytrichioides), 

 linear- subulate, less rigid than in the last-named species, and 

 spreading in a more lax manner, spinuloso-dentate, but only 

 toothed at the back of the nerve near the apex. At the lower 

 extremity the very wide membranaceous sheath is of a fine pur- 

 plish pink colour. Seta three-fourths of an inch in length. 

 Capsule with the operculum, resembling that of D. polytrichi- 

 oides, but twice as large. 



Dawsonia superba; procera, foliis uncialibus, rigidiusculis, sublaxe 



patentibus. Plate XII. 

 Hab. Australia. 



♦ Read before the Botanical Society of Edinburgh, March 11, 1847. 



