Vascular Plant Herbarium

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NOTES ON THE PSIDIUM SALUTARE COMPLEX

A revision of this complex is found in Sida 20(4): 1449-1469 (2003). At this site you can find a key to the taxa, images of the taxa, and lists of exsiccatae. The complex is considered to consist of just two species, P. laruotteanum and P. salutare, the latter with five varieties.

How is Psidium distinguished?  Psidium is distinguished from other genera by a combination of floral and seed characters discussed in Landrum and Sharp [Landrum, L. R. and W. P. Sharp. 1989. Seed coat characters of some American Myrtinae (Myrtaceae): Psidium and related genera. Systematic Botany 14(3): 370-376], namely, flowers 5-merous with multiovulate locules; placenta often peltate; seed coat rough or dull, not lustrous, covered with a pulpy layer when wet; hard portion of seed coat (5--)8--30 cells thick at narrowest point, the cells thick-walled, elongate, overlapping.

How is the Psidium salutare complex distinguished?  The P. salutare complex is differentiated from other species of the genus by 1) a usual habit of subshrub or shrub (but reaching tree size in some populations); 2) a habitat mainly of grasslands or low shrubby growth (cerrado) that is frequently burned; 3) an ability to sprout back from underground stems even after fires; 4) leaves with brochidodromous venation with a well marked marginal vein that closely follows the margin and tertiary veins that form a reticulate-dendritic pattern; 5) relatively small flower buds (4--9 mm) with the calyx open; and 6) a peltate placenta with one or two rows of ovules on the edge of the each lamina.

List of exsiccatae for Psidium laruotteanum

List of exsiccatae for Psidium salutare

Key to the species and varieties of the Psidium salutare complex:

1. Young leaves densely covered with hairs beneath, the lower surface of the leaf often hidden.

2. Leaves silvery lanate, usually less that 1.5 cm wide; apex usually sharply acute to abruptly acuminate; hairs of leaves of two lengths, short and tangled and long and nearly straight; Argentina, Uruguay, Bolivia, Paraguay, Rio Grande do Sul (Brazil)
...................................................................................P. salutare var. sericeum

2. Leaves yellowish to grayish short tomentose, often over 1.5 cm wide; apex acute to rounded; hairs of leaves uniform in length, all tangled; Paraguay, Bolivia, Paraná (Brazil), north to Venezuela and Costa Rica.............................P. laruotteanum

1. Young leaves glabrous to moderately pubescent beneath.

3. Venation clearly evident above and below, the marginal vein within 1 mm of the margin; leaves often narrowly elliptic or lanceolate, often 3 or more times as long as wide, often lustrous; leaf apex often apiculate; calyx-lobes longer than calyx tube plus hypanthial tube; Argentina, Uruguay, Paraguay, Rio Grande do Sul, Santa Catarina, Paraná....................................................P. salutare var. mucronatum

3. Venation clearly evident or not, the marginal vein usually more than 1 mm from the margin; leaves mostly less than 3 times as long as wide, lustrous or not; leaf apex usually without an apiculum; calyx-lobes longer or shorter than calyx tube plus hypanthial tube.

4. Leaves narrowly elliptic to elliptic, mostly less than 1.5 cm wide, the apex usually rounded; peduncle 0.5--1.5 cm long; Paraná to Goiás................................................Psidium salutare var. decussatum

4. Leaves various, often lanceolate, usually over 2 cm wide, the apex often acute; peduncle 0.4--3 cm long; Paraguay to Mexico and Caribbean.

5. Leaves 4 to 9 cm long, 2--5 cm wide, elliptic to obovate; usually shrubs to small trees; plants glabrous; central Brazil, Bolivia to Venezuela........................................Psidium salutare var. pohlianum

5. Leaves 3.3 to 7 cm long, 1--3.3 cm wide, usually lanceolate, ovate, or elliptic; normally subshrubs; plants glabrous or pubescent; Paraguay to Mexico and Caribbean.........................Psidium salutare var. salutare