128 REPORT— 1871. 



valuable as a medicinal agent, and which, without due care and attention on the 

 part of collectors, might ultimately become scarce or be eradicated in its native 

 coimtry. 



On the Flora of Cfreenland. By Robert Brown, M.A., Ph.D., F.B.G.S. 



An account of researches on the Phyto-geographical aspect of the Greenland 

 flora compared with that of other portions of the arctic regions, the causes which 

 conduced to it, and most general facts relating to the arctic flora, chiefly in rela- 

 tion to Dr. Hooker's classical memoir on the subject in the Linnean Transactions 



(vol. XXV.). 



On the OeograpJiical Distribution of the Floras of North-west America. 

 By Egbert Brown, M.A., Ph.D., F.R.G.S. 



After studying the subject for nearly four years, during travels through all parts 

 of the country to the west of the Rocky Mountains, Dr. Brown considered that 

 instead of one homogenous flora in North-west America there are in reality five, viz. 

 (1) The great flora of the region to the west of the Cascades and Sierra Nevada 

 Mountains. (2) The flora between this range and the Rocky Mountains. (3) The 

 Montane flora on the summits of the mountains about 4000 feet, chiefly arctic. 

 (4) The flora of the Colorado descent. (5) The Athabascan flora, or the flora to 

 the coimtry. 



On Specimens of Fossil-wood from the Base of the Lower Carboniferous BocJcs 

 at Langton, Berwichshire. By the Rev. Thomas Brown. 



Suggestions on Fruit Classification. By Professor A. Dickson. 



0>» the minute Anatomy of the Stem of the Screw-Pine, Pandanus utilis. By 

 W. T. Thiselton Dyer, B.A., B.Sc, Professor of Botany in the Royal 

 College of Science for Ireland. 



Except that the tissues are less indurated, the general structure of the stem and 

 the arrangement of the fibro-vascular bundles resemble that met with in palms. 

 The bundles, however, are somewhat remarkable from containing vessels which be- 

 long to the scalariform type. In a ti-ansverse section these bundles are seen to be- 

 come smaller towards the circumference and more condensed, forming a well-de- 

 fined boundary to the narrow cortical portion of the stem. The bundles are, how- 

 ever, continued through the cortical portion, but are reduced to little more than a 

 thread of prosenchyma. In the cortex there are numerous large cells containing 

 raphides : these also occur in the rest of the stem, but are less frequent. Crystals 

 of another kind are found in connexion with the fibro-vascular bundles. These are 

 contained each in a square-shaped cell, forming part of a string or chain. A number 

 of these strings or chains are distributed round the circumference of each iihro- 

 vascular bundle ; they are especially abundant in its cortical continuation, as they 

 do not suffer a degradation proportionate to that of the other constituent tissues. 

 This peculiar arrangement ot crystal-bearing cells seems probably unique. The 

 crystals are four-sided prisms with pyramidal apices. They are almost certainly 

 composed of calcium oxalate, though they are too minute and isolated with too much 

 difficulty to allow of their satisfactory examination. 



On the so-called 'Mimicry ' in Plants. By W. T. Thiselton Dter, B.A., 

 B.Sc, Professor of Botany in the Itoyal College of Science for Ireland. 



In all large natural families of plants there is a more or less distinctly observable 

 general habit or fades, easily recognizable by the practised botanist, but not always 

 as easily to be expressed in "words. The existence of such a general habit in legu- 



