L2 



MEMOIRS OF THE NEW YORK BOTANICAL GARDEN 



[VOL. 10 



2. Xyris fallax Malme, Bihang Sv. Vet.-akad. Handl. 22, Afd. 3, No. 2: 12. 



pi. 1, f. 5. 1896. 



X dolichosperma Lanjouw, Bee. Trav. Bot. Neerl. 34: 488. /. 5. 1937. Type. In savannis 

 humidis prope Zanderij I, Suriname, Pulle 39 (U). 



Type. Santa Anna da Chapada, Mato Grosso, Brazil, G. Malme 1432 (S). 



Distribution. Common in savanna areas, eastern Colombia, Venezuela, British 

 Guiana and Suriname, and south to Mato Grosso, Brazil. Especially frequent in 

 Guayana to altitudes up to 1500 m, and often in the field confused with X. caro- 

 liniana but readily distinguished from that species by its multicostate scapes, 

 and nerved dorsal area. 



3. Xyris erythema Maguire & Smith, sp. nov. Pig. 1, A-F. 



Herbae acaules perennes, rhizomatibus horizontalibus, 4 mm diam. ; foliis 

 equitantibus, lateraliter valde compressis, 20-42 cm longis, crasse laxeque ner- 

 vatis, praesertim ad nervos transverse rugulosis, plus minusve roseo-suffusis, 

 basin versus rubro-brunneis ; vaginis ad 14 cm longis, basin versus gradatim 

 ampliatis, apice eligulatis et in laminas confluentibus, intus dense brunneo- 

 ciliatis ; laminis linearibus, falcato-acutis, 8 mm latis ; scapo erecto, rigido, 

 25-68 cm alto, multicostato, praesertim ad costas tuberculato; spica ovoidea, 

 12-15 mm longa, multiflora ; bracteis infimis valde reductis, bracteis fertilibus 

 obovatis, late rotundatis, sepala superantibus, brunneis, glabris, integris, area 

 dorsali bene distincta, subelliptica, viridi-grisea, linea mediana praedita; sepalis 

 lateralibus liberis, lanceolatis, acutis, 4.5 mm longis, subaequilateralibus, carina 

 lata, apicem versus irregulariter serrulata ; staminodiis penicillatis ; placentis 

 parietalibus ; seminibus immaturis solum cognitis, paucis, fusiformibus, apice 

 albo-appendiculatis. 



Type. Leaves stiff, reddish-brown toward base, brittle, flowers yellow, infre- 

 quent in wet places, scrub and low forest (8-10 m), on shoulder of east flank, 

 above Thompson Camp, alt. 1418-1525 m, 10 Aug 1960, Upper Mazaruni River 

 Basin, Mt. Ayanganna, British Guiana, S. S. & C. L. Tillett & R. Boyan 45074 

 (holotype NY, isotype US). Paratypes. British Guiana, Merume Mts., Partang 

 River : along ridge trail, alt. 1140 m, infrequent in marshy areas in forest, 3 Jul 

 1960, Tillett & Boyan 43974; frequent on sand and rocks of stream bed, Tillett 

 & Boyan 43998. 



This species is closely related to Xyris fallax Malme, as evidenced by its 

 multicostate scapes and by the practically identical form of the seeds. However, 

 it is strikingly differentiated by the presence of rhizomes and coarsely and laxly 

 nerved rugulose leaves that are often suffused with a brilliant red hue. 



Distribution. Known only from the Merume and Ayanganna uplands of the 

 Pakaraima Mountains, British Guiana, apparently there to the exclusion of its 

 close relative X. fallax. 



II. Section Nematopus Seubert in Martius, Fl. Bras. 3 1 : 211. 1855. 



Key to the Species of Section Nematopus ' 



1. Basal bract (at least one) or bracts elongate, usually exceeding those immediately 

 above. 



2. Basal bracts f oliaceous ; scape bialate. 



3. Leaves much shorter than the scape, 4-6 mm wide; basal sterile bracts numerous, 



spreading to reflexed. 4. X. involucrata- 



