Monographs Details: Maguireothamnus speciosus (N.E.Br.) Steyerm.
Authority: Maguire, Bassett & Wurdack, John J. 1964. The botany of the Guayana Highland--Part V. Mem. New York Bot. Gard. 10: 1-278.
Family:Rubiaceae
Description:Distribution and Ecology - Distribution. Slopes and summits of sandstone table mountains of Venezuela from Mount Roraima and Serra do Sol on the east by the British Guiana and Venezuelan frontiers respectively west to Auyan-tepui, in estado Bolivar. This is the most widely distributed species of the genus. VENEZUELA. Bolivar: summit, Roraima; alt. 8600 ft; autumn 1898, Mc Connell & Quelch 653 (photo of holotype of Chalepophyllum speciosum, from K at NY); summit. Mount Roraima; flower large, huffy-white, with red outside the involutions; leaves oval, stiff, opposite; 24 Nov 1927, Tate 388 (NY) of Mount Roraima; corolla with spreading-recurving lobes, white within, without white with deep rose-red on one margin; corolla-tube pale green; flowers very fragrant; leaves coriaceous, shining and deep green above, margined brick or dull reddish; corolla lobes in bud reddish; 27 Sep 1944, Steyermark 58860 (F, NY, VEN); Ptari-tepui; Bonnetia roraimae forest on southwest-facing shoulder alt. 2000-2200 m ; shrub 3 ft tall; flowers sweet-fragrant; corolla-tube pale brick, lobes white; 2 Nov 1944, Steyermark 59740 (F, NY); Ptari-tepui; south-facing forested slopes vicinity of ''Cave Rock"; alt. 1800-1900 m; 2 Nov 1944, Steyermark 59801 (NY, VEN); summit of Serra do Sol; occasional; alt. 2300 m; shrub 1-1.5 m tall; petals white, rose-margined; 28 Dec 1954, B. Maguire & C. K. Maguire 40392 (NY); Mount Auyan-tepui; alt. 2200 m; Dec 1937, Tate 1179 (holotype of Chalepophyllum coriaceum. NY, isotype VEN); Chimanta Massif, headwaters of Rio Tirica; frequent; rocky and swampy savanna; alt. 2120-2210 m; depressed shrub 1 m tall; 11 Feb 1955, Steyermark & Wurdack 743 (F, NY, VEN) ; Chimanta Massif, vicinity of Summit Camp along Rio Tirica; frequent; alt. 1925 m ; 20 Feb 1955, Steyermark & Wurdack 1004 (F, NY, VEN); Chimanta Massif, Apacara-tepui; swampy savanna; alt. 2000-2100 m; 20 Jun 1953, Steyermark 75781 (F, NY, VEN); Chimanta Massif, Abacapa-tepui; Bonnetia forest; alt. 2125-2300 m; 13 Apr 1953, Steyermark 74881 (F, NY, VEN); Auyan-tepui; alt. 2300 m; Apr 1956, Vareschi & Foldats 4858 (VEN); Auyan-tepui; dominante en la formacion arbustiva; alt. 1900 m ; Apr 1956, Foldats 2603 (VEN); Auyantepui; alt. 2100 m ; Enero 1949, Cardona 2669 (VEN); Chimanta Massif, northwest cumbres, Churi-tepui (Muru-tepui); occasional; alt. 2250-2300 m; 26 Jan 1953, Wurdack 34209 (NY); Chimanta Massif, lower part of lower cumbre, Churi-tepui (Muru-tepui); alt. 2100-2200 m; 24 Jan 1953, Wurdack 34178 (NY).

Discussion:

Fig. 76, A-C.

Chalepophyllum speciosum N. E. Brown, Trans. Linn. Soc. II. 6: 33. pl. 5, f,g. 10-17. 1901; Standley, Field Mus. Bot. Ser. 7: 381. 1931.

Chalepophyllum coriaceum Gleason, Brittonia 3: 192. 1939.

At the time Gleason described Chcdepophyllum coriaceum (Brittonia 3: 192. 1939), he contra.sted it with C. speciosum N. E. Brown of Mount Roraima. Gleason attempted to differentiate C. coriaceum on the basis of its longer internodes, shorter erect-appressed prolongation of the stipule, leaf-blades more cuneately narrowed at the base, and broader corolla-lobes less attenuate at the apex. These differences do not hold, however, as evidenced by an examination of all available material.

In his original description of Chalepophyllum speciosum N. E. Brown states that the leaves are "cuneate at the base" (Trans. Linn. Soc. II. 6: 33. pl. 5, fig. 10-17. 1901). This condition may be largely observed in the original plate accompanying the description as well as in the photograph of the holotype collection by Mc Connell & Quelch from the summit of Mount Roraima (NY). However, there is considerable variation in the character of the leaf-base, even in topotypical material. For example, Tate 388, a topotype from the summit of Roraima, has the base of the leaf-blades obtuse to obtusish, while Steyermark 58860, also a topotype, has a cuneate leaf-base on one of the sheets at NY, but a duplicate specimen at VEN and on another sheet at NY shows the leaf-base obtuse or obtusish. There appears to be no fundamental difference between the cuneatebased leaves of the Roraima C. speciosum and those of the Auyan-tepui C. coriaceum. Both taxa show overlapping variations in shape and apex of the leaves.

Similarly, with respect to variation in length of internode and prolongation of stipule, no correlation can be found in these characters between the plants of Roraima (where Chalepophyllum speciosum was described) and those of Auyantepui (where ChalepophyUum coriaceum was described), or in those plants collected on Ptari-tepui, Chimanta Massif, and Serra do Sol. Gleason described his C. coriaceum as having the acumen of the stipules "erect, appressed" and "2-4 long" with internodes "mostly 1.5-3 cm long" (loc. cit. p. 192), contrasting this with C. speciosum which, according to him, had stipules "much longer and more or less spreading" and internodes "only 1-10 mm long." Unfortunately, these differences, likewise, do not hold, variations in internode length and stipule length occurring on the same plants. Where the specimen has been collected from elongated vegetative shoots or from a portion of the main thicker branch, the internodes show, for the most part, greater lengths than those of the short lateral and upper terminal shoots. There is as much crowding of the internodes on flowering and fruiting branches of plants from Roraima (type locality of Chalepophyllum speciosum) as from those of Auyan-tepui (type locality of C. coriaceum). In the original plate illustrating C. speciosum the internodes are shown varying from short and crowded (4-5 mm long) on the branch at the lower side of the reproduction to longer (8-11 mm long) on the branch at the right side of the same illustration. All degrees of variation are exhibited on collections from Chimanta Massif, the collections of Steyermark & Wurdack 1004 having prolongations of the stipules 2-2.5 mm long, while Steyermark 75781 has stipule prolongations of 5-6 mm long on elongated vegetative shoots. Topotype material of C. speciosum from Roraima (represented by Tate 388, Steyermark 58860, and Mc Connell & Quelch 653) shows internodes from 3-8 mm long and stipule tips from 3-5 mm long, whereas holotype and topotype material of C. coriaceum from Auyan-tepui (represented by Tate 1179, Cardona 2669, Foldats 2603, and Vareschi & Foldats 4858) has internodes ranging from 3-20 mm long and stipule tips from 2-4 mm long. Collections from Chimanta Massif have internodes ranging from 3-14 mm long and stipule tips from 2-6 mm. Collections from Ptari-tepui have internodes 3-5 mm long (Steyermark 59740) to 10-15 mm long (Steyermark 59801) and stipule tips from 2-3.5 mm long.

As regards length of corolla-tube and length and shape of corolla-lobes, great variation is encountered. On topotypical material from Mount Roraima of Chalepophyllum speciosum the corolla-tube varies from 45-90 mm long, the corolla-lobes from 25-50 m m long and mainly 7-12 mm broad (4 mm in dried wrinkled material), while in topotypical material from Auyan-tepui of C. coriaceum the corolla-tube varies from 70-100 mm long, the corolla-lobes from 20-36 mm long and 7-12 mm broad. Specimens from Chimanta Massif range from corolla-tube lengths of 65-115 mm long and corolla-lobes 25-48 mm long and 7-15 mm broad. From Ptari-tepui the length of the corolla-tube measures 85-90 mm long, the corolla-lobes 35 mm long by 7-8 m m broad. Specimens from Serra do Sol (Maguire & Maguire 40392) show the greatest extremes in width of corolla-lobes, these having a width of 14-19 mm. The length of 40-47 mm in this latter collection is matched by a Wurdack 34209 collection from Chimanta Massif having corolla-lobes 42-48 mm long but a width of 9-11 mm. There is too much intergradation in corolla-lobe width to segregate the Serra do Sol collection. So far as corolla-lobe width, there are overlapping and non-correlating variations in width among the range of material passing as Chalepophyllum. speciosum and C. coriaceum. Also, in many specimens the corolla-lobes are not pressed equally flat, resulting in some shrinkage with measurements of Avidth less than in wellpressed or living material.

Gleason believed that the plants of his C. coriaceum had more broadly acute and less narrowly pointed tips to the corolla-lobes than the narrower, more attenuate apices found in the Roraima material of C. speciosum, but later topotype collections of C. coriaceum from Auyan-tepui (Cardona 2669) and of the nearby Chimanta Massif show as narrow corolla-lobes with as attenuate apices as those of C. speciosum. Moreover, other collections from Chimanta show various degrees of corolla-lobe width and apex attenuation.

Most of the stipules and their prolongations are completely glabrous throughout. A collection from Ptari-tepui (Steyermark 59740) has stipules strigose on the upper margins and linear-cuspidate prolongations of the apex, but from the same table mountain another collection (Steyermark 59801) varies from stipules completely glabrous to strigose on the tips and upper margins on the branch on the left hand side of the sheet in the Herbario Nacional of Venezuela. A topotype of C. speciosum from Mount Roraima (Tate 388) also shows the stipule prolongation and upper margins sparsely strigose, while other collections from Roraima (Steyermark 58860) exhibit both glabrous and sparsely strigose conditions.

Distribution:Venezuela South America| Guyana South America|