Monographs Details: Monotrema affine Maguire
Authority: Maguire, Bassett & Wurdack, John J. 1958. The botany of the Guayana Highland--Part III. Mem. New York Bot. Gard. 10: 1-156.
Family:Rapateaceae
Scientific Name:Monotrema affine Maguire
Description:Latin Diagnosis - Herbae terrestres perennes, caudice erecto vel suberecto 2-5 cm alto; foliis 5-7 in quoque tempore, 30-50 cm longis; vaginis 8-12 cm longis, ad basim 15-20 mm latis, nee equitantibus nee distiche dispositis; laminis 20-40 cm longis, 6-8 mm latis, glabris, gramineis, 9-13 nervatis; foliis veteribus marcescentibus; pedunculis axillaribus 1 vel 2 per folium, 5-7 dm longis, ca. 1 mm diam., quadrangularibus, 6-costatis; capitulis solitariis, 12-15 mm longis; bracteis primariis 1-2, ovato-lanceolatis, 15-20 mm longis, ad basim 6-10 mm latis, acutis, cum 9-13 nervis principalibus; bracteis secondariis numerosis ca. 20-30 ferme spiculas subtendentibus, bracteis oblongo-lanceolatis, 10-13 mm longis, 3-5 mm latis, marginibus scariosis, apicibus obtusis, minute aristatulis; spiculis 15-25, stipitatis, stipitibus ca. 1 mm longis; bracteolis 5-7, 6-7 mm longis, aliquantum acutis; petalis flavidis, 6-7 mm longis, unguibus ca. 2 mm longis, laminis lanceolatis acutis, 4—5 mm longis; staminibus 6, antheris ca. 4 mm longis, ad basim 4-thecatis, uniporis, poris oblique terminalibus; ovario evidenter non maturo.

Distribution and Ecology - Paratypes: Yapacana Savannas: herbaceous perennial forming hummocks in caatinga, Savanna III, Dec 31, 1950, Maguire, Cowan & Wurdack 30488; frequent, edge Savanna III, March 17, 1953, Maguire & Wurdack 34535; perennial herb with yellow flowers, Savanna III, March 17, 1953, Maguire & Wurdack 34566; perennial herb 50-70 cm high, outer bracts greenish, inner white, bearing straw-colored pale yellow flowers, occurring where Monotretna iracteatum & M. xyridoides grow together, occasional in Savanna III, Nov 20, 1953, Maguire, Wurdack & Bunting 36570; infrequent in open woodland near Savanna I, Nov 20, 1953, Maguire, Wurdack & Bunting 36607.

Discussion:

Type: herbaceous perennial 5-7 dm high, bracteoles white, petals pale yellow, frequent in sparse savanna bush, north edge of Savanna III, 125 m alt., Rio Orinoco, Terr. Amazonas, Venezuela, Nov 20, 1953, Maguire, Wurdack & Bunting 36611 (holotype NY).

There is suggestive evidence that Monotrema affine is a sterile hybrid between M. bract eat um and M. xyridoides. In stature M. affine is usually somewhat larger than either of the others. In floral characters it seems to be somewhat intermediate between them, but the bracteoles are scarious-margined, a character that does not obtain in either of the other two. In material examined, no mature ovary or seed was found, although pollen seemed normal. And finally, this possible hybrid occurs only in the presence of the two suspected parents, so is thus confined, so far as known, to the Yapacana Savannas, to which M. bracteatum also is limited. M. xyridoides is of more extended distribution, but in its additional range occurs without the presence of either M. bracteatum or M. affine.