Petrie. — On a new Species of Uncinia. 185 



Prevention. 



Although the seed is fine, almost dust-like, its presence 

 amongst other seeds may be detected by a careful observer, 

 although not apparent to the untrained eye. When any species 

 of Orobanche becomes established, I believe it might be easily 

 destroyed by prompt mowing close to the soil, if the operation 

 be performed before the seed-vessels arrive at maturity ; a care- 

 ful watch should be kept, and any new shoots that make their 

 appearance cut down at once. 



Probably Orobanche ramosa, the broom-rape of the hemp, 

 would withstand this process, but I know of no other species 

 possessing any great power of resistance. 



I may close this short paper by advising agriculturists to 

 purchase their seeds from seedsmen who give a guarantee of the 

 purity of their stock, as in the case of some English houses. 

 At present, comparatively few seeds are grown in New Zealand, 

 but I am sure that any qualified persons, taking up the business 

 of seed-growing with proper means and appliances, would 

 obtain a fair annual return without other protection than the 

 cost of packing, freight and insurance, especially if prepared to 

 give a guarantee of the purity and vitality of their seeds. 



Art. XXV. — Description of a new Species of Uncinia, Persoon. 

 By D. Petrie, M.A., F.L.S. 



[Read before the Otago Institute, 8th November, 1887.] 



Uncinia clarkii, n. s. 



A spreading species, forming a close grass-like sward. 



Leaves somewhat shorter than the full-grown culms, grassy, 

 smooth or slightly scabnd at the edges, fiat with prominent 

 midribs, J^ - i inch wide, 6-9 inches long. 



Culms, 12 inches high or less, terete, rather stout, smooth, 

 strongly grooved. 



Spikelets, H-2 inches long ; male portion short ; bract short 

 and setaceous or none. 



Glumes, closely imbricate, as long as the utricles, lanceolate, 

 acute or sub-acute, membranous, pale-brown, attached more 

 than half-round to the rachis, deciduous, leaving when shed a 

 semicircular cup-like projection below the attachment of the 

 utricles, which gives the rachis a curious jointed appearance ; 

 male glumes more persistent. 



Utricles, small, dark-brown, stipitate below and tapering 

 above, half as long as the recurved bristle, strongly divaricating 

 when mature, faintly nerved on the outer surface. 



