1963] 



BOTANY OF THE GUAYANA HIGHLANDS PART V 



7 



XYRIDALES 4 



In the natural order Xyridales there has in the past been presented a re- 

 view of the Guayana representatives as follows: Orectanthe, 5 AboVboda, 5 and 

 Achlyphila 6 of the Xyridaceae, and with the exception of Rapatea and Stegolepis 

 but including Maschalocephalus of Africa, the sixteen genera of the Rapate- 

 aceae. 7 There are now presented herewith supplementary notes on Abolboda and 

 our treatment of Guayana Xyris. There yet remains a detailed consideration of 

 the two rapateaceous genera, Rapatea and Stegolepis, to complete the survey of 

 Guayana Xyridales. 



XYRIDACEAE 



Abolboda Kunth in Humboldt & Bonpland, PI. Aequin. 2: 25. 1809. 

 Abolboda minima Maguire, sp. nov. 



A. killipii Lasser affinis sed spicis unifloris et foliis laevibus. 



Herbae tenuiter perennes, acaulescentes ; foliis numerosis, rosulatis subtereti- 

 bus laevibus, 2-12 mm longi, 0.4-0.5 mm diam., minutissimis serrulatis (ad 20 

 mag.), abrupte truncatis, unilateraliter mucronatis, basi expansa scariosa amplec- 

 tanti ; scapis nullis ; spica uniflora ; bracteis paucis lanciacuminatis, scariosis, 

 planis, ca. 5 mm longis, 1-nervis; sepalis 2, conduplicatis, lanceolatis, pungenter 

 acuminatis, scariosis, dorsaliter firmis, 7-9 mm longis; corollis albidis essentiali- 

 ter regularibus 12-13 mm longis, tubo hypocrateriformi ca. 8.5 mm longo, lobis 

 orbiculari-obovatis, retusis, 4-5 mm longis ; staminodiis evidenter nullis ; stamini- 

 bus 3; filamentis planis, 1-nervatis, ad tubum adnatis, supra 0.6-0.8 mm liberis; 

 antheris oblongo-sagittatis, 1.0-1.2 mm longis, granis pollinis sphaeroideis, non 

 aperturatis, spinosis, 110-120^ diam., sporodermate ca. 10 /x crassa ; stylo ca. 8 

 mm longo, appendicibus 2 ; stigmate hypocrateriformi fimbriato ; ovario ovali ; 

 seminibus non visis. 



Type. Flowers very pale blue, fading white, locally abundant in Sabana 

 Manacal, 15 km above Guarinumo, alt. 125-140 in, Rio Atabapo, 12 Jun 1959, 

 Amazonas, Venezuela, J. J. Wurdack & L. S. Adderley 42977 (holotype NY). 

 Paratype. Flowers pale blue, locally occasional in Sabana El Venado on left 

 bank of Carlo Pimichm above Pimichm, alt. 140 m, Rio Guainia, 2 Jul 1959, 

 Amazonas, Venezuela, J. J. Wurdack & L. S. Adderley 43296. 



Distribution. Known only from the type region. 

 Abolboda minima is clearly allied to A. killipii and A. acaulis, both of which 

 have well-developed spicules, each with several flowers subtended by relatively 

 broad, falcate, firm sepals. In leaf -form our new plant is most like A. killipii, but 

 it lacks the foliar ornamentation of that species. 



Abolboda ebracteata Maguire & Wurdack, Mem. N. Y. Bot. Gard. 10: 17. 1958. 



Abolboda ebracteata var. ebracteata. 



A small scapose herb with cephalar bracts long-productate and exceeding the 

 florets ; and long (6-12 cm), linear, convolute leaves. Known only from the Yapa- 

 cana Savannas on the Alto Orinoco. 



4 By Bassett Maguire and Lyman B. Smith, 

 s Mem. N. Y. Bot. Gard. 10 1 : 1-19. 1958. 

 e Mem. N. Y. Bot. Gard. 10 2 : 12-14. 1960. 

 7 Mem. N. Y. Bot. Gard. 10 1 : 19-49. 1958. 



