antheris suborbiculari-reniformibus, 0.5 mm. altis, 0.7 
mm. latis; filamenti parte libera 0.5 mm. longa; floribus 
foemineis basi inflorescentiae solitariis sessilibus; calycis 
foeminei laciniis ovatis, acutis, 1.8 mm. longis, 1-1.5 mm. 
latis, extus ferrugineo-tomentosis sed marginibus serru- 
latis glabris; stylis arcuato-recurvato-patentibus, 0.8 
mm. longis, apice breviter bilobatis; ovario ferrugineo- 
tomentoso, 8 mm. longo (Plate XVI). 
Senefelderopsis Croizatu is a dominant member of the 
forest of dwarfed trees and shrubs occurring on the south- 
eastern basal slopes of Carrao-tepui, and was seen only 
on this part of the area, really an extension of Ptari-tepui 
table mountain. In cutting a trail through the part of 
the forest where this species occurred on the way up to 
the summit of Carrao-tepui, the copious latex would 
exude abundantly from the stems every time the machete 
was used to cut through overhanging or pendent branches 
of this species. With the easily cut stems covered by the 
white latex, it was no effort to spot the trail on the re- 
turn trip from the summit of this mountain to camp. 
VenezuELa: State of Bolivar, southeastern portion of base of Carrao- 
tepui, alt. 1460-1615 m., ‘‘tree 25-40 feet tall; one of dominant 
trees in dwarfed woods; milky latex abundant; trunk straight; leaves 
coriaceous, deep green above, silvery white below, margins subrevo- 
lute; rose-purple; rhachis mustard greenish-yellow; flowers yellow. ’”’ 
December 4-5, 1944, Julian A. Steyermark 60849 (Tyre in Herb. 
Chicago Nat. Hist. Mus.). 
Senefelderopsis chiribiquetensis (Schultes & 
Croizat) Steyermark comb. nov. 
Senefeldera chiribiquetensis Schultes & Croizat in Cald- 
asia 8 (1944) 122, fig. 
This second Colombian species, found in the Depart- 
ment of Vaupés in southeastern Colombia on one of the 
isolated sandstone mesas, Mount Chiribiquete (or Cerro 
Comején), in the Upper Apaporis Basin along the Ma- 
[ 47 ] 
