Arabis.] 



CRUCIFER^. 



41 



semi-amplexicaulibus glabris subdentatis, floribus siliquisque linearibus elongatis paten- 

 tissimk,— Graham in Edin. New Phil, Journ. July, 1829. p. 7. [not EhrL nor Willd.) 



«. follis radicalibus parce pubescentibus. 



^. foliis radicalibus pubescenti-incanis subintegris. 



Facies T.strictm; difFert insigniter, etiam in cultu, floribus siliquisque patentissimis. 

 Fhres majusculi, pulcherrime purpureo-rosei. 



Hab. a. From Canada to lat. 68°, and from Hudson's Bay to the Rocky Mountains. Dr. Jiichardson. 

 Drummond; and even to Fort Vancouver on the Columbia. Douglas, Scouler. /3. Hig^hest summits of the 

 Rocky Mountains. Drummond, — Pods long, curved. Professor Hornemami has sent me tlie var, /3. from 

 Greenland. 



5, T, retrofracta; erecta, incano-pubescens vel glaber, foliis lanceolatis, radicalibus 

 petiolatis dentatis, caulinis sagittatis semi-amplexicaulibus glabris subdentatis, floribus 

 cernuis, siliquis linearibus elongatis pedicellisque retrofractis, — Arabis retrofracta. Graham 

 in Edin. New Phil, Journ. July^ 1829. p. 1. 



Hab. Hudson's Bay to the Rocky Mountains; and from Canada to lat. 68°; at the Mackenzie River. 

 Dr. Richardson. Drummond, — This is at once distinguishable from the two preceding species, which are its 

 near allies, by the deflexed dowers, (which are mostly pure white, or with a faint purplish tinge,) and by the 

 retrofracted pedicels and pods. The seeds are in two rows, or series, in a young state, and are then quite 

 pendent; afterwards, by their enlargement, they lie more horizontally in the cell, and form but one series, as 

 Dr. Graham remarks : but it would be better to abolish one of the two genera, than, by putting this into 

 Arabis, to separate it from T. stricta and T. patula, with which it is so closely and so naturally allied. 



6. T,l diffusa; glaberrima, glauca, caulibus ramosis diff'usis, foliis radicalibus spathu- 

 latis subinteoris, caulinis sagittatis vix dentatis, siliquis linearibus patentibus pedicello 

 duplo longioribus. 



Radix parva, subfusiformis, ut videtur, annua. Caules plurimi ex eadem radice, diffusl, glabri, ramosi, 

 subspithamsei. Folia radicalia pliirima, in rosulam expansa, parva, spathulata, subintegerrima, petiolo lon- 

 ^usculo : caulina majora, subunciam longa, oblonga vel lanceolata, basi dilatata, sagittata, apice obtusa, mar- 

 gine integerrima, vel, hie iUic, dente instructa, glaberrima, glauco-viridia. Flores parvi. Calyx glaber, 

 sepalis ovalibus, sequalibus, pedicello glaberrimo trlplo brevioribus. Petala calyce dimidio longiora, alba, 

 obovata, unguiculata. Siliqum vix unciam longie, patentes, lineares, obtusae, stigmate parvo subsessili ter- 

 minatae, nondum maturse semina seu ovula in duas lineas disposita, exhibentes. 



Hab. Shores of the Arctic Sea. Dr. Richardson.— This may probably prove an Arabis; but in the 

 scarcely mature seed-vessels two rows of ovules are evident, which, however, may, as in T. retrofracta, 

 when ripe, arrange themselves in one series. But whether an Arahis or a Turritis, I know of no specie* 

 with which it can be confounded. It is probably scarce, as few specimens exist in the collection, and those 

 only in Dr. Richardson's portion of it. 



5. ARABIS. Linn, 



Siliqua linearis; valvis planis medio uninerviis. Semina in quoque loculo 1-seralia, 

 ovalia aut orbicularia, compressa. Cotyledones planae. (o^.) Flores albi, aut rarius 



rosei. DC, 



* Semina immarginata, seu parva ala membranacea cincta, DC. 



1. A. alpina; subdifFusa, ramosa, foliis pluri-dentatis pube ramosa villosis lanceo- 

 latis acutis, radicalibus subpetiolatis, caulinis cordato-amplexicaulibus, pedicellis calyce 



VOL. I. 



