Monographs Details: Ugni myricoides var. roraimensis (N.E.Br.) McVaugh
Authority: Maguire, Bassett. 1969. The botany of the Guayana Highland-part VIII. Mem. New York Bot. Gard. 18: 1-290.
Family:Myrtaceae
Discussion:

Myrtus roraimensis K.E. Brown, Trans. Linn. Soc. 11. 6: 26. 1901.

Ugni roraimensis (N.E.Brown) Burret, Notizbl. Berlin 15: 507. 1941.

Myrtus myricoides var roraimensis (N. E. Brown) Steyerm., Fieldiana Bot. 28: 1022. 1957.

This appears to be the nearest to what may be called a generalized taxon in the Guayana mountains. Described from Roraima, it is known also from other tepuis in the same region. Although not sharply distinct from Ugni myricoides var myricoides, it is usually recognizable by the partial or complete absence of pubescence, the smaller and often crowded leaves, and the smaller flowers. The lectotype, M c Connell & Quelch 635, which I studied at K in 1966, is a sparingly pubescent plant with relatively broad and scarcely 2-ranked leaves, i.e., like U. myricoides var myricoides in this respect. A paratype at K, McConnell & Quelch 641, is almost glabrous, with narrower leaves.

Steyermark (Fieldiana Bot. 2 8 : 1021. 1957) noted the occurrence on Roraima of an assemblage of variants including typical Ugni roraimensis (the glabrous form); more pubescent forms resembling typical U. myricoides; narrow-leaved forms like f stenophylla; and forms intermediate in leaf-shape and other features between f stenophylla and var roraimensis (e.g., Steyermark 58770, with pubescent flowers, and essentially glabrous leaves 2-3.5 m m wide and three times as long, but pubescent branchlets). Further field observation is needed. Other variants include plants with longer calyx-lobes; these plants are almost indistinguishable from U. myricoides var myricoides of the Andes (e.g., McConnell & Quelch 495, at K, from the summit of Roraima). One specimen from near the summit, im Thurn 189 (K) has pedicels 1.5 cm long, in this respect resembling North American material. Evidently the species is much more variable here than in the Andes, but the precise patterns of variation remain to be worked out. Some of the extreme forms are described below.

The following I should refer to Ugni myricoides var roraimensis: V E N E Z U E L A. Bolivar: Mt. Roraima, summit, elev 2620 m, 7 Jan 1939 (fl, fr), Pinkus 102, p.p. (F); summit, 24 Nov 1927 (fr), Tate 405 (K); just below summit, 27 Sep 1944 (fl), Steyermark 58782 (F), summit (fl, fr), Steyermark 58833 (F); southwestern plateau, 7/1/1939 (fr), Forest Dept. 2879 (K); Chimanta Massif, Agparamantepui, below escarpment, elev 1880-1955 m, 26 Feb 1955 (fl, fr), Steyermark & Wurdack 1142 ( M I C H ) ; Auyan-tepui, elev 2100 m, Jan 1949 (fl, fr), F. Cardona 2718 ( N Y ) ; Auyan-tepui, cumbre de la parte sur, near El Libertador, 2050-2300 m, 15 M a y 1964 (fl), Steyermark 93973 ( M I C H ) ; Auyan-tepui, 2300 m, Apr 1956 (sterile), Vareschi & Foldats 4889 ( N Y ).

Occasional white-pubescent plants with crowded two-ranked leaves, from Roraima, are difficult to separate from f bifaria, described below. See for example, Pinkus 102, p.p. (F), or McConnell & Quelch 495, p.p. (K). Ugni vaccinioides Burret (Notizbl. Berlin 15: 506. 1941), described from Roraima, is said to have had the branchlets "dense albo-hirti" and the peduncle "densiuscule albo-hirtus," the leaves oval, the calyx-lobes 1.5-2 m m long. I have not seen the specimens cited by Burret {Ule 8700, type; v. Luetzelburg 21613, paratype), but from the description I suppose them to have been somewhat like the Pinkus specimen cited above.

The following collections have the short flowers of Ugni myricoides var roraimensis, but in pubescence and in leaf-size they resemble U. myricoides var myricoides: V E N E Z U E L A . Bolivar: Ptari-tepui, base of bluffs, elev 2410-2450 m, 7 Nov 1944 (fr), Steyermark 59946 (F); Roraima, below summit, elev 2560-2620 m, 27 Sep 1944 (fr), Steyermark 58783 (F).