372 NEW SPECIES OF DIAPENSIA. 



On a new Species (/Diapensia, from the Eastern Himalaya; by J. D. 



Hooker, M.D., F.R.S, etc. (With a Plate, Tab. XII.) 



Of the genus Diapensia only one species, D. Lapponica, (or two, if 

 the Pyxidanthera barbulata be included,) have hitherto been described. 

 The Pyxidanthera is a native of the north-eastern United States of 

 America. The D. Lapponica is a much more widely distributed plant, 

 being common in the Arctic regions of Europe, Asia, and America, at- 

 taining the seventh parallel, and also occurring on the alps of Scandi- 

 navia, and at an elevation of 4500-6500 feet in the White Mountains 

 of New Hampshire. 



The species now to be described is the only Central Asiatic repre- 

 sentative of the genus, and is apparently a very local Himalayan plant, 

 occurring nowhere to the westward of the longitude of Sikkim, where 

 it is seen on wet rocks and banks in the humid subalpine valleys, at 

 elevations of 10-14,000 feet ; it does not however inhabit either the 



■ 



outer ranges or the drier interior valleys. In its native state it so en- 

 tirely resembles a Primida in its flower, that Linuseus's having assigned 

 it a place in the same Natural Order (Predates) with most of the Pro- 

 mulacea, was a very natural error. The true affinities of the genus 

 are however no doubt with Ericece. In habit and foliage D. Lapponica 

 and Himalaica very much resemble Loiseleuria procumbens, and in the 

 structure of their flowers they are still more closely allied to the Hima- 

 layan genus Diplarche, described and figured at vol. vi. p. 382. t. 11 

 of this work, and referred to the tribe Rhodorece of Ericete. To that 

 tribe I would append Diapensia^ the only point of difference appearing 

 to be the absence of a hypogynous disc, and the insertion of the sta- 

 mens at the mouth of the corolla instead of towards its base ; in this 

 latter respect the stamens represent the upper series in Diplarche, 

 which are inserted above the middle of the tube of the corolla. The 

 other points of affinity between Diapensia and Ericece have been dwelt 

 upon by various botanists, and including, as they do, the whole struc- 

 turc? of the ovary and ovules, carpels and placentation, albumen and 

 embryo, they are of themselves almost sufficient to establish its place 

 in the Natural System. Amongst the less important points of diffe- 

 rence between Diapensia and the tribe Rhodorece are the absence of any 

 indusium, or thickened termination of the cuticle surrounding the 

 stigmatic surfaces, the petaloid or broad filaments, and the divarica- 

 ting anthers. In the ■ Flora Antarctica,' vol. ii. p. 332, I have alluded 



