Monographs Details: Psidium riparium Mart. ex DC.
Authority: Maguire, Bassett. 1969. The botany of the Guayana Highland-part VIII. Mem. New York Bot. Gard. 18: 1-290.
Family:Myrtaceae
Description:Distribution and Ecology - BRAZIL. Without locahty, Martius (M, type). Para: "In vicinibus Santarem,"Spruce 316 ["Myrcia (9)"] (M, type of P paraense; C G E , G, K, M I C H , N Y , isotypes);Tucuruy, praia Niteroi, 10 July 1949 (bud). Black 8035 (MICH; a formwith long peduncles, long petioles, dense pubescence); Igarape Remansinho, RioTocantins, 8 Sep 1948 (imm fr), Froes 23417 ( M I C H ) ; "Para, Siber [sic]" (BR,annotated by Berg, type of P sieberianum ß robustum Berg); without name of collectoror locahty (BR, annotated by Berg, type of P. sieberianum a gracile Berg);Fl. Tapajoz, Santarem, Spruce 393 (P); Santarem, Riedel 1571 (K). Matto Grosso:5. Moore 624 (BM, type of P insulincola; N Y , isotype); Cuyaba, Aug? 1892 (fl),Kuntze sn (NY, holotype of Myrtus thyrsodea); Serra do Roncador, road betweenChavantina and Carapu, 27 Sep 1964 (imm fr). Prance & Silva 59145 (MICH).Goias: Rio Maranhao, Pohl (W, lectotype of P. maranhense).

Discussion:

Psidium paraense Berg, Mart. Fl. Bras. 14(1): 386. 1857.

Psidium maranhense Berg, Mart. FI. Bras. 14(1): 386. 1857.

Psidium sieberianum Berg, Mart. Fl. Bras. 14(1): 387. 1857.

Psidium insulincola S. Moore, Trans. Linn. Soc. IL 4: 353. 1895.

Myrtus thyrsodea O. Kuntze, Rev. Gen. 3(2): 92. 1898.

Psidium thyrsodeum (O. Kuntze) K. Schum., Just Bot. Jahresb. 26(l): 359. 1900.

Apparently all the above names pertain to the same taxon. Individual specimens differ in density of pubescence, and in length of peduncles and petioles. The leaves are sessile or essentially so in the types of Psidium riparium (cf Field Mus. neg. 19722!, photo of type at M ) , P maranhense (Field Mus. neg. 31426), P paraense, and P insulincola; in P. thyrsodeum the petioles are up to 4 m m long, and in P. sieberianum they are considerably longer. In some modern specimens referred to P. sieberianum they may be as much as 15 m m long. The leaves in almost ah specimens are cordate at base, but in forms with long petioles the blades may be rounded at base and unequally decurrent upon the petioles.

In the original material of P. paraense the racemes usuahy bear 1 short-pedunculate flower at a node, and the peduncles are 2-4 m m long; in all other specimens examined, the peduncles are longer, 1-2.5 cm long, and often 3-flowered.

Branchlets and inflorescence (except the coroha) are consistently hirsute. I do not find any differences in type of pubescence or in patterns of distribution of the hairs, except that in the less strongly pubescent individuals the foliar hairs are confined to the midvein on the upper surface, whereas in the most pubescent plants the hairs may extend onto the petioles and leaf-surfaces.

In other respects all the specimens are alike to the minutest details, and I believe the variations noted above are not taxonomically important unless it can be shown that they are correlated with some other variables

As thus broadly delimited, Psidium riparium ranges widely south' of the Amazon, approaching the mouth of that stream from the south, but apparently not crossing it to the north. In the protologue the type-locality of P. riparium was given merely as "in Brasilia ad fluminum ripas." The type, a Martius specimen at M , annotated by de Candolle, bears the label by Martius, "in ripa flum. cum Asclepiade vicinale." If this is the same Asclepias vicinale that was ultimately published (as a synonym, in Mart. Fl. Bras. 6(4): 236. 1885), the type-locahty is on the Rio S. Francisco near Joazeiro, that is, in Bahia.

Distribution:Brazil South America|