Myrcia inaequiloba (DC.) Legrand

  • Authority

    Maguire, Bassett. 1969. The botany of the Guayana Highland-part VIII. Mem. New York Bot. Gard. 18: 1-290.

  • Family

    Myrtaceae

  • Scientific Name

    Myrcia inaequiloba (DC.) Legrand

  • Description

    Distribution and Ecology - VENEZUELA. Amazonas: Puerto Ayacucho, elev 100-120 m, 8 Nov 1953 (fl),Maguire et al 36065 (MICH); Culebra savanna, N W base of Cerro Duida, elev200 m, Nov 1950 (fl), Maguire et al 29417, 29777 (both M I C H ) ; Rio Cunucunuma,Culebra Rapids, elev 200 m, 23 Dec 1950 (imm fr), Maguire et al 30360 (MICH).Bolivar: Rio Pargueni, elev 100-150 m, 10 Dec 1955 (fl), Wurdack & Monachino39761 (MICH); Sierra Ichun, Rio Ichun (trib. Rio Paragua), elev 500 m, 28 Dec1961 (fl, imm fr), Steyermark 90312 (MICH, NY) ; Sierra Auraima, raudal de ElPerro, elev 400 m, 16 Jan 1962 (old fl), Steyermark 90826 ( M I C H ) ; Cerro Guaiquinima,Rio Paragua, raudal Ouraima, elev 175 m, Dec-Jan 1951-52 (fl, imm fr),Maguire 32718, 32719, 33155 (ah M I C H ) ; Salto de Auraima, elev 275 m, 10 Apr1943 (fr), Killip 37338 (F); Hato la Vergarena, Rio Aro below Cafio Azul, elev390 m, 29 Mar 1955 (bud, imm fr), Wurdack 244 (MICH), 30 Mar 1955 (fr),Wurdack 253 (MICH); alto Rio Caroni, raudal Tukaika, elev 425 m, 4 Oct 1946(bud), F Cardona 1683 (G, NY) ; raudales Karukuya, elev 740 m, 9 Oct 1946 (bud),Cardona 1795 (NY) ; vicinity of Uriman, elev 300 m, 30 Apr 1953 (imm fr), Steyermark75305 (MICH); (fl), Steyermark 75331 (MICH); Chimanta Massif, RioApacara, elev 400 m, 25 Mar 1953 (imm fr), Stcvermark 74645 (MICH), 415 m,29 Mar 1953 (imm fr), Steyermark 74704 (INIICH); Torono-tepui, along Rio Tirica'500-515 m, 9 Mar 1955 (imm fr), Steyermark & Wurdack 1314 (MICH), 470 m,16 Jan 1955 (bud, fl), Steyermark & Wurdack 127 (NY), 131 ( M I C H ) ; Rio Karaui

  • Discussion

    Eugenia inaequilobaDCyDC.Frodr. S: 282. 1828.

    Eugenia ? nitida Benth., Jour. Bot. Hook. 2:322. 1840, non. Camb.

    Eugenia polyantha Miq., Linnaea 18: 741. 1844.

    Aulomyrcia pirarensis Berg, Linnaea 27: 41. 1855.

    Aulomyrcia paniculata Berg, Linnaea 27: 49. 1855.

    Myrciaria ? polyantha (Miq.) Berg, Linnaea 27: 322. 1856.

    Myrciaria nitida (Benth.) Berg, Linnaea 27: 324. 1856.

    Aulomyrcia lancifolia Berg, Linnaea 30: 658. 1861.

    Aulomyrcia inaequiloba (DC.) Amsh., Rec. Trav. Bot. Neerl. 42: 7. 1950

    Aulomyrcia inaeqidloba var nitida (Benth.) Amsh., Rec. Trav. Bot. Neerl. 42: 8 1950

    Aulomyrcia inaequiloba var paniculata (Berg) Amsh., Rec. Trav. Bot. Xeeri. 42: 7. 1950 Widespread and often cohected especially in British Guiana and in southeastern Venezuela, this species is easily recognized by the impressed midvein, the glabrous flowers on strongly reddish-pubescent panicle-branches, the thin pale unequal calyx lobes that are pubescent within, and the persistent bracts. The corky-rimose petioles of Marlierea umbraticola seem to provide a useful method of differentiating that species from Myrcia inaequiloba even when flowers are not available. As discussed above, Myrcia inaequiloba combines a number of the features of sect Armeriela in a way that emphasizes the weaknesses of the distinctions between Myrcia and Marlierea. The hairs are mostly basifixed (as in Myrcia); the inflorescence is that of Myrcia (cf M e m . N. Y. Bot. Gard. 10(1): 63. 1958), but the persistent bracts of the inflorescence are common in Marlierea but not in Myrcia; the thin-margined hypanthium flattens after anthesis (as in Marlierea), but does not develop radial fissures; the calyx-lobes are very unequal in size (usually three larger and two or sometimes one smaller), thin and petaloid, often falling away from the hypanthium at maturity (as in Marlierea). A comparison between Myrcia inaequiloba and Marlierea umbraticola confirms what has been implied above, namely that certain species-pairs in the two genera must be separated quite arbitrarily on the basis of the splitting or nonsplitting of the hypanthium. In Marlierea umbraticola the bud is almost closed, but bears 4 minute calyx-lobes at the tip; in anthesis the fissures in the hypanthium extend well beyond the staminal ring, nearly to the center of the flower. Except for this one feature of the hypanthium, the resemblances between Marlierea umbraticola and Myrcia inaequiloba are very close, even extending to details of pubescence, foliar morphology, branching of the inflorescence, size and disposition of the bracts, and flower-structure in general. Since Berg's time this species has usually been referred to Aulomyrcia, but Berg himself did not fully understand it. In his treatment in Linnaea (1855-1856) he described it at least four times, under two different names in Aulomyrcia and two in Myrciaria. W h e n he established the genus Myrciaria (Linnaea 27: 320. 1856), he recognized within it a group he called Paniculatae, comprising six species from the Guianas and two from Brazil. Presumably Berg included this group in Myrciaria because of the prevailingly 4-merous flowers of most species, the tendency for the calyx to split irregularly in anthesis, and the consistently bilocular ovary with two ovules in each locule, as in Myrciaria. Apparently he did not have an opportunity to study fruit of any of the species of Paniculatae (although he mentions the "berry" of M . nitida), and so did not realize the myrcioid affinities of the group, in spite of the characteristic branching of the inflorescence in the Guiana species. Four of the latter were first described as species of Eugenia {Eugenia polyantha Miq., E. quilarensis Benth., E. schaueriana Miq., E. nitida Benth.). In recent times it has been generally realized that the Paniculatae are quite out of place in Myrciaria, and the Guiana species have been transferred to Myrcia or Aulomyrcia. The type-material of Eugenia inaequiloba consists of 2 sheets in G - D C ; one, which may be considered as lectotype, is a flowering specimen marked "Cayenne," and annotated in the hands of de Candolle. The other is a fruiting specimen, not annotated by de Candolle but represented by Field Mus. neg. 7943. Both specimens are good representatives of Myrcia inaequiloba in the sense of this paper. The name M . inaequiloba was pubhshed provisionally, but not validly, by Lemee (Fl. Guy. Frang. 3: 150. 1954). The t)^e-locality of Aulomyrcia paniculata was given as "ad flumen Essequibo in Guiana Anghca," and the collector "Rich. Schomb., coll. no. 296," "v.s. in hb. Berol." It is assumed that the type has been destroyed. I have not located any specimens annotated by Berg. A Schomburgk specimen at W , represented by Field Mus. neg. 31490, was distributed from Berlin at an early date under the name A. paniculata, but lacks the collector's number and has not been annotated by Berg Evidently no. 296 and no. 306 represented the same gathering, at least in the opinion of the Schomburgks; see below under A. pirarensis. The type-collection of Aulomyrcia pirarensis was Rob. Schomburgk 306, said to have come from Pirara, British Guiana, "v.s. in hb. Vindob." I have seen the type at W , and duplicates at B M , G, M I C H , K(hb. Benth.). Another sheet at K is numbered 306/296B; in accordance with the numbering system used by the Schomburgk brothers (see the introduction to this paper), it may be supposed that 296 was the number assigned to the same gathering in Richard Schomburgk's set at Berlin. The Berlin specimen of this number became the type of A. paniculata. Amshoff has noted as her opinion on a sheet of no. 306, at Kew, that probably two forms of the same species were collected under this number, viz, "pirarensis" with blunter thicker leaves, and "paniculata" with more acuminate and less coriaceous leaves. In view of the fact that the type-locality of A. pirarensis was given as Pirara, and that of A. paniculata as on the Essequibo River, it may be that the Schomburgks collected the plant twice, and combined the gatherings under a single number. The two forms observed by Amshoff may be compared in Field Mus. neg. 31492, representing the type of A. pirarensis (at W ) , and Field Mus. neg. 23336, representing a sheet of no. 306 at G. The differences between the two seem to represent individual variations; I should refer all the specimens to Myrcia inaequiloba. Amshoff proposed Aulomyrcia inaequiloba var paniculata, differing "from the typical form by the thinner, long-acuminate leaves and more slender petioles," and A. inaequiloba var nitida, with leaves like those of A. inaequiloba var paniculata but the inflorescence "more or less white-villous, with brown hairs intermixed," and the calyx sometimes 5-merous. I cannot recognize any distinct populations on the basis of leaf-shape or pubescence, although it is true that in this species there is a considerable variation between forms that are almost glabrous and those with abundant pale pubescence.

    Closely related to Myrcia inaequiloba, and perhaps not a distinct species, is Aulomyrcia obtusata Berg (Linnaea 27: 39. 1855) based on "Rich. Schomburgk, coll. no. 1085; Rob. Schomburgk, coh. no. 704," "v.s. in hb. Berol. et Vindob." A usual under the numbering system employed by the Schomburgk brothers (see the introduction to this paper), it is probable that Berg saw no. 1085 at Berlin; it is assumed that this collection has been destroyed. A sheet of no. 704, at W , named by Berg, may therefore be taken as lectotype; additional isotype material has been seen as follows: No. 704 (BM, M I C H , W ) ; no. 704/1085B (K); no. 1085 (K, ex hb. Berol. 1859, det. Berg). The plant resembles M . inaequiloba except that it has narrow obtuse leaves 3-4.5 cm long, 1-1.8 cm wide, and the inflorescence is rather shorter than usual; in other respects, e.g., impressed midvein, pubescent inflorescence, glabrous hypanthium, thin pale unequal calyx-lobes that are pubescent within, it exactly simulates M . inaequiloba. The original collections were supposedly from Roraima; I have not seen any others like them except the following. VENEZUELA. Bolivar: OriUas de Caroni, en playas y raudales Curucuya, 9 Oct 1946 (bud), Cardona 1787 (US).

  • Distribution

    V E N E Z U E L A . Amazonas: Puerto Ayacucho, elev 100-120 m, 8 Nov 1953 (fl),Maguire et al 36065 (MICH); Culebra savanna, N W base of Cerro Duida, elev200 m, Nov 1950 (fl), Maguire et al 29417, 29777 (both M I C H ) ; Rio Cunucunuma,Culebra Rapids, elev 200 m, 23 Dec 1950 (imm fr), Maguire et al 30360 (MICH).Bolivar: Rio Pargueni, elev 100-150 m, 10 Dec 1955 (fl), Wurdack & Monachino39761 (MICH); Sierra Ichun, Rio Ichun (trib. Rio Paragua), elev 500 m, 28 Dec1961 (fl, imm fr), Steyermark 90312

    Venezuela South America|