396 Sir R. Schomburgk on some Grasses and Sedges 



their operations according to circumstances, and when unimpeded 

 m them, of the beauty and fitness of their architectural eleva- 

 tions. 



EXPLANATION OF PLATE XXIII. 



Fig. 1. Stethorectus ingens, female, natural size. 



Fig. 2» Ditto male ditto : a, wing, natural size. The following are mag- 

 nified: b, labial palpi ; c, maxillary palpi ; d y mandible of the female ; 

 e, mandible of male ;/, antennae of the male. 



XLI. — Description of some Grasses and Sedges from the East 

 Coast of Demerara, with Remarks on the Geographical Distri- 

 bution of the Species. By Sir Robert Schomburgk, Ph.D., 

 Member of the Imperial Academy Nat. Curios. &c. 



The grasses and sedges are to a flat alluvial soil what the forests 

 are to a hill-side ; their interlacing roots render the soil firm and 

 prevent it from being carried away by the surface waters, which 

 chiefly during freshets under the tropics commit such ravages 

 upon low lands. The grassy sward protects besides the ground 

 beneath from the direct rays of the sun, which possess such in- 

 creased power in the equatorial regions. As great as the benefit 

 derived from these circumstances may have proved to certain 

 localities on our globe, if the use which the grasses afford to 

 mankind rested only upon these circumstances, they would never 

 have been considered of that vast importance which is attached 

 to this natural family. If we set aside that their seeds afford 

 nourishment to millions of human beings, their herbage serves 

 as food to millions of cattle which in their turn contribute to the 

 support of mankind. It is not my object to dwell here on these 

 important points, but merely to give an enumeration of some 

 grasses and a few of the sedges which occur in the intermediate 

 neighbourhood of the sea-coast in Demerara, and the greater 

 number of which are used as fodder. It must not be considered 

 that this list contains all the Graminacese of that locality, — their 

 number might be tripled ; they were merely the result of short 

 botanical excursions in the neighbourhood of Georgetown and to 

 Mon Repos, a sugar-plantation on the east coast of Demerara ; 

 a few I received from Mr. Garnett at Cuming's Lodge, about six 

 miles east from Georgetown. This small collection was sub- 

 mitted to the examination of Professor Nees von Esenbeck, the 

 great illustrator of Graminacese and Cyperacese, who with his 

 usual kindness has described those peculiarities in which the 

 Demerara specimens deviate from former descriptions of species. 

 It is worthy of observation that these deviations amounted in no 

 instance to specific differences. 



I have added the vernacular names under which the species and 



