353 



PEAESONIA, A NEW GENUS OF LEGUMINOS^. 



By K. a. DiJMMER. 



(Plate 522.) 



While engaged on an enumeration of the species constituting 

 the genera Lotononis and Pleiospora, it became apparent that 

 the presence of certain units in the former genus threatened the 

 stabihty of both genera, and to obviate this, and to lessen at the 

 same time the acute polymorphism existent in Lotononis, this new 

 genus has been founded. Pearsonia occupies a position in the 

 tribe Genisteae intermediate between Lotononis and Pleiosjjora; 

 it is differentiated from the latter by its exstipulate, sessile or 

 very shortly petiolate leaves, scarcely inflated calyces, 12-30 ovuli- 

 ferous ovaries, and longer legumes, which are never included 

 within the calyces, while the straight style " with its correlated, 

 straight carina emphasise, its distinctness from Lotononis. 



The genus is primarily founded on Lotononis sessiUfolia of 

 Harvey, who, evidently recognizing the peculiarities of the species, 

 placed it at the end of that genus in a section wholly opposed to 

 this procedure. The genus as at present established contains 

 eleven species, and being entirely South African, I have pleasure 

 in dedicating it to Prof. Dr. H. H. W. Pearson, whose energy in 

 matters pertaining to South African botany is too well known and 

 appreciated to need any comment. 



PEARSONIA Diimmer. 



Genus novum PleiosporcB Harvey affinis, sed foliis exstipulatis 

 sessilibus aut breviter petiolatis, ovario 12-30 ovulato, leguminibus 

 calyce duplo aut ad quatior longioribus distat. 



Calyx Lotononidis. Vexillum breviter unguiculatum, rectum, 

 concavum, oblongum vel oblongo-spatulatum, carinam aequans 

 aut excedens ; alae rectse, limbis saepissime conduplicatis oblique 

 obovatis vel oblongis, unguibus longis superne saepius tortuosis ; 

 carina recta, longe unguiculata, limbo parvulo anguste navicular! 

 obtuso, marginibus superioribus conduplicatis. Stamina omnia 

 in vaginam supra limberam connata, antheris brevioribus basifixis, 

 alternis longioribus dorsifixis et paullulo majoribus. Ovarinm 

 sessile, 12-30 ovulatum ; stylus rectus, ovario saepissime brevier, 

 stigmate verticaliter truncato aut saBpe oblique truncato interdum 

 papillato. Legumen calycem valde excedens, oblongo-lanceolatum, 

 rectum, compressiusculum, 2-valve. Scmina estrophiolata, funi- 

 culis incrassatis brevibus. — HerbcB e basi lignoso ramosae (rarius 

 frutices divaricati), saepissime fulvo sericeae, raro glabrae, caulibus 

 annuis plerumque rectis subsimplicibus. Folia trifoliolata, ex- 

 stipulata. Flores bracteati bracteolatique in racemos terminales 

 congesti aut laxe dispositi, rarissime solitarii, flavidi. Species 11 

 omnes Africcs australis incolce. 



* This applies to the flowering not the fruiting stage. 



Journal of Botany. — Vol. 50. [Dec. 1912.] 2 c 



