Key to the Woody Plants of Estación Biológica Cocha Cashu, Parque Nacional de Manu, Perú

This key is cribbed, almost verbatim, from Alwyn Gentry's incomparable book A Field Guide to the Families and Genera of Woody Plants of Northwest South America. This greatly simplified key includes only taxa likely to be found in the vicinity of Manu. It focuses on the species found in lowland floodplain (varzea) forest, but also includes taxa from upland, never-flooded terra-firme forest. It is written, for the most part to the family level, but individually distinctive genera and species are also included.

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Indicated Family

1:	Leaves Simple

Look for axillary buds, and don't be confused by compound leaves

1:	Leaves Alternate

1 leaf per node

Trees

Totally free-standing plants, but be careful - liana saplings may be temporarily free-standing!

Smell?

Break a leaf or twig. Smells are often faint

1:	Avacadoish, stinky, clustered leaves

Lauraceae

2:	Strong bark, "fishnet" inner bark on twigs

Annonaceae

3:	Leaves evenly spaced, branches horizontal and +/- whorled

Myristicaceae

smell often is faint

4:	Spicy, and swollen nodes

Piperaceae

5:	Petiole flattened or grooved

Talauma amazonica (Magnoliaceae)

rare

6:	Tomatoish, stinky

Solanaceae

7:	Almonds!, and big glands at base of leaf undersurface

Prunus vana (Rosaceae)

Rare - but cool!

Latex?

Break a leaf, petiole, twig, or slash the trunk

1:	Latex white, margins always entire

Petioles swollen and apically tapered

Pouteria and relatives (Sapotaceae)

2° veins finely parallel

Chrysophyllum and relatives (Sapotaceae)

2:	Conical terminal stipule (or at least scars!) present, latex white, 'cafe con leche', rarely yellowish-brown

Moraceae

Conical terminal stipule: A pointy structure at the branchlet apex to protect the developing leaf

3:	Serrate and/or with glands on leaf or petiole

Euphorbiaceae

4:	Latex thin and red

Myristicaceae

5:	Latex scanty, in the longish curved petioles

Olacaceae

6:	Latex white, plentiful, often with crazy fenestrated trunk

Apocynaceae (mostly Aspidiosperma)

3:	Conical terminal stipule

A pointy structure at the branchlet apex to protect the developing leaf. leaves a scar that (mostly) encircles the twig at each node

1:	Latex + conical terminal stipule

Moraceae

2:	Ochrea present

Polygonaceae

Ochrea: a membrane that encloses the developing leaf, and ruptures as the new leaf expands

4:	3 or more principal veins

Palmately veined: three or more veins originating at the base of the leaf

1:	Pulvinus present at petiole apex

Pulvinus: and area notably more flexible than the rest of the petiole. The "wrist" of a leaf.

1:	Leaves serrate

Tiliaceae

2:	Leaves entire, or very jaggedly serrate if in early-successional area

Sterculiaceae

3:	Leaves entire and oblong

Bombacaceae

4:	Plant shrubby, or more or less climbing

Malvaceae

5:	Small trees with shiny leaves

Bixa (Bixaceae)

2:	Pulvinus at petiole apex absent

Petiole texture is consistent from base to apex

1:	Leaf bases asymmetric, frequently asperous

Ulmaceae

2:	Leaves membranous, frequently with urticating (stinging) hairs

Urticaceae

Careful! almost always pioneer species

3:	Glands on leaf blade or petiole

Euphorbiaceae

4:	Either with petiole glands, or side-veins that reach almost to tip of leaf, or foliaceous stipules

Flacourtiaceae

5:	Shiny leaves, 3-veined to apex

Zizyphus cinamomea (Rhamnaceae)

6:	Treelets with long wiry petioles

Abuta grandifolia (Menispermaceae)

5:	Strong Bark

Pick at it with a fingernail - bark that comes off as a strip is "strong bark"

1:	All bark layers peel as one, and leaves serrulate

Lecythidaceae

Rare in floodplain

2:	And with ranalean odor

Annonaceae

3:	Twig bark amazingly strong, small treelets

Thymelaceae

Rare

6:	Unequal petiole lengths

1:	Leaves terminally clustered, small trees

Capparidaceae

2:	Mostly (but not all!) serrate

Euphorbiaceae

3:	Swollen petiole apex, deciduous

Sterculia (Sterculiaceae)

Rank odor

Araliaceae

Rare, mostly in uplands

7:	Petiole glands

1:	Gritty, red inner bark layer

Chrysobalanaceae

Glands not always notable, but the inner bark is - cut the bark with a knife.

2:	Leaves clustered at tips of short-shoot branches

Combretaceae

Clustering is often very strong, and notable on its own.

8:	Serrate Margins

Even if just barely serrate - look carefully, feel with a finger or tongue

1:	Mostly huge trees, small leaves serrulate, mixed alternate and opposite leaves

Sloanea (Elaeocarpaceae)

2:	With (sometimes linear) punctations, and (often caducous) stipules

Flacourtiaceae

3:	Grooved petiole

Calatola (Icacinaceae)

4:	3° veins parallel and perpendicular to midvein, small trees

Lacistema (Lacistemataceae)

5:	Many ascending faint 2° veins, serrulate

Lecointea (Fabaceae)

6:	Small shrubs, with non-pellucid punctations (blackish dots) on leaves

Myrsinaceae

7:	Very sharp teeth, many curving 2° veins

Ouratea (Ochnaceae)

8:	Broadly jagged or toothed

Solanaceae

9:	Unbranched treelets

Clavija (Theophrastaceae)

10:	Non-descript, caducous stipules leaving scar on twig

Violaceae

11:	Quite non-descript

Richeria, Acidoton (Euphorbiaceae)

9:	Flexed petiole apices

But not flexible - not pulvinate

1:	Mixed opposite and alternate leaves

Sloanea (Elaocarpaceae)

2:	Non-descript, longish petioles

Caryodendron, Sagotia (Euphorbiaceae)

3:	Non-descript, shortish petioles

Flacourtiaceae

4:	Serrulate, leaf blade tapers onto swollen petiole apex

Allophylus amazonicus (Sapindaceae)

10:	Punctations

Hold leaf toward the light, try with 10x hand lens

1:	Stipules or stipule scars

Flacourtiaceae

common

2:	Clustered leaves

Rutaceae

rare

3:	Punctations non-pellucid (ie, blackish), no stipules

Myrsinaceae

small trees or shrubs

4:	Parallel 3° veins

Caraipa densifolia (Clusiaceae)

11:

Stipules

Small growths on either side of the petiole bases, to protect the next developing bud. Also look for linear scars at the leaf bases where stipules have fallen. Try with 10X hand lens. You may need to try all four of these families.

1:	Only on young twigs, gritty reddish inner bark

Chrysobalanaceae

2:	Very non-descript

Chaetocarpus, Margaritaria, Sagotia (Euphorbiaceae)

3:	Even more non-descript

Casearia (Flacourtiaceae)

4:	Horribly non-descript. Look for remains of ramiflorous fruit on trunk.

Leonia, Paypayrola (Violaceae)

12:	Lepidote scales or stellate trichomes

Use a hand lens - look for shiny dots or branched hairs

1:	Trichomes variously branched and dendroid

Solanaceae

Piny odor

Duguetia (Annonaceae)

3:	A few nasties

Croton, Hieronyma, Pera Euphorbiaceae

13:	3° Veins parallel

1:	Leaf blade poorly distinguished from petiole

Agonandra brasiliensis (Opiliaceae)

2:	Punctate leaves

Caraipa densifolia (Clusiaceae)

3:	White latex (sometimes not obvious)

Sapotaceae (some)

14:	Non-descript oddballs

These are weird enough that you basically have to learn each species separately. Luckily, they (almost) all have some easy characteristic

1:	Stems hairy, nodes frequently swollen with ants, or, leaves arising from dichotomously branching horizontal twigs

Cordia (Boraginaceae)

2:	Grooved petiole

Catatola (Icacinaceae)

3:	Non-descript Lauraceae-like leaves

Violaceae

4:	Small trees with heavy, dark leaves

Maytenus (Celastraceae)

5:	Flowers at apex of petioles of otherwise non-descript leaves

Tapura (Dichapetalaceae)

6:	Leaves apically clustered, usually on short-shoot branches, sometimes with petiole glands

Combretaceae

7:	Blackish inner bark, scattered glands on leaf-undersurface

Diospyros (Ebenaceae)

8:	Left-over genera of Euphorbiaceae

Drypetes, Margaritaria, (Euphorbiaceae)

9:	U-shaped petiole thickened at apex, usually with a trace of white latex

Olacaceae

10:	Strong garlic odor, thin leaves, long petioles

Gallesia integrifolia (Phytolaccaceae)

11:	Ochea, a sheath that developing leaves rip through, or scars thereof

Polygonaceae

12:	Unbranched shrub, with narrow clustered leaves

Dilkea retusa (Passifloraceae)

rare

Lianas

Or scrambler, at least partly dependent on other plants

1:	Tendrils present?

1:	Tendril axillary, usually with glands

Passiflora (Passifloraceae)

2:	Tendril emerging at 90° to petiole base

1:	Leaves usually palmate veined, often lobed or toothed

Cucurbitaceae

2:	Nodes swollen, often palmate veined or 3-5 foliate

Cissus (Vitaceae)

3:	Stipules modified to form tendrils

Smilax (Smilacaceae)

A monocot, but you'd never know by the net-veined leaves

4:	Tendril coiled in one plane

Gouania (Rhamnaceae)

"Like a butterfly's tongue", fide Gentry.

2:	No tendrils

1:	Leaves serrate

Asperous

Dillenaceae

2:	Three-veined, with spines

Celtis iguanea (Ulmaceae)

3:	Leaves membranaceous

Urticaceae

4:	In swamps, oddly-raised petiole attachment(only subserrate)

Corynostylis arborea (Violaceae)

5:	Three-veined, usually with glands

Omphalea, Pluknetia (Euphorbiaceae)

Smell?

Crush a leaf or twig. All these are pretty uncommon.

1:	Swollen nodes

Piperaceae

2:	Palmate veination, veins branching into lower lobes

Aristolochiaceae

3:	Spicy and three-veined

Sparattanthelium tarapotanum (Hernandiaceae)

4:	Wierd, w/o chlorophyll

Cassytha (Lauraceae)

Rare

3:	Palmate veination

3+ main veins arising at base of leaf

1:	Wiry petiole apex, or petiole base very flexible

Menispermaceae

2:	Pulvinate petiole apex and stellate trichomes

Byttneria (Sterculiaceae)

Latex

Not that useful a charter for alternate simple-leaved lianas

1:	Pinnately veined leaves with cordate bases

Ipomoea and relatives (Convulvulaceae)

2:	Spiny branches, yellow bark and looped 2° veins

Maclura brasiliensis (Moraceae)

Spines

1:	Raised nodes with paired spines

Seguieria (Phytolaccaceae)

2:	Inconspiculous prickles on stem, leaves with indistinct veination

Moutabea (Polygalaceae)

3:	Recurved prickles, and usually stellate trichomes

Solanaceae

2:	Leaves opposite

2 or more leaves per node

Trees

Freestanding woody plants

1:	Stipules present

Small projections between the petiole bases (or rarely between petiole and twig). Check branchlet tips, and look for the scars left by fallen petioles

1:	Default choice should be:

Rubiaceae

2:	Stipules narrow, leaves serrate

Quiina (Quiinaceae)

much less common than Rubiaceae

3:	Stipules intra-petiolar (in leaf axils)

Byrsonima and Bunchosia (Malphigiaceae)

4:	Stipules thick-based, often falling to leave glands

Vochysiaceae

rare

Latex

1:	Lots of white latex

Apocynaceae

2:	Latex usually colored, often with terminal bud buried between leaves at tip of branchlet

Clusiaceae

3:	Punctations

use at least a 10x hand lens, and look towards the light

1:	Many 2° veins with collecting vein, some with nice smellling leaves, many with smooth reddish peeling bark

2:	Like above, and therefore very tricky, looks nothing like the rest of its family!

Mouriri (Melastomataceae)

4:	3-7 main veins, and ladder-like 2° veins

:	Melastomataceae

Melastomataceae

5:	Pleasant odor

Crush a leaf

1:	This should be the default choice.

Myrtaceae

Sometimes the punctations, which are almost always present, are not obvious.

2:	leaves furry below, or with a very few sharp teeth

Mollinedia (Monimiaceae)

sometimes as few as 2-3!

3:	Sweet clear odor, squarish stems, and often flattened nodes

Verbenaceae and Lamiaceae (only herbs)

4:	Swollen nodes and sheathing petiole bases

Hedyosmum (Chloranthaceae)

very rare

6:	Serrations

1:	Often with parallel 3° veins and pale leaf undersides, small trees

Hippocrataceae

2:	Extremely common small tree, short petiole

Rinorea (Violaceae)

3:	Very few teeth, slight nice odor

Mollinedia (Monimiaceae)

7:	Non-descript

1:	Common and non-descript, usually with rufescent terminal bud and leaf pairs of differing sizes

Neea (Nyctaginaceae)

Very common small trees, and a total pain

2:	Tetragonal branches and flattened nodes, often with elongate gland on petiole apex

Verbenaceae

3:	Hollowed-out petiole base to protect developiing bud

Chrysochlamys (Clusiaceae)

4:	Few sharp, erect spines, legumelike odor and cylindrical petioles

Polygala scleroxylon (Polygalaceae)

5:	Very thick, coriaceous large leaves

Salacia (Hippocrataceae)

6:	Occelate glands on leaf base below, and T-shaped trichomes

Malpighiaceae

Lianas

Climbing by means of tendrils, twining, spines, or leaning

1:	T-shaped trichomes

hairs that branch in 2 directions, use a 10x hand lens

:	Malphigiaceae

Malphigiaceae

2:	Milky Latex

1:	More woody, less viney

Apocynaceae

2:	Less woody, more viney

Asclepidaceae

3:	3-veined leaves

1:	With a few thick tendrils

Strychnos (Loganiaceae)

2:	Ladder-like 2° veins

Melastomataceae

4:	Miscellaneous others

Serrate

Hippocrataceae

2:	Mucilage in stems, great sprays of flowers in fry season

Combretaceae (mostly Combretum)

3:	Viny, with swollen nodes

Mendoncia (Acanthaceae)

4:	Subwoody hemiepiphyte, often anisiphyllous (pairs of leaves of different sizes)

Gesneriaceae

5:	Nodes flattened, with asperous leaves

Petrea aspera (Verbenaceae)

6:	Nasty curved spines, clustered leaves

Pisonia aculeata (Nyctaginaceae) and Uncaria guianensis (Rubiaceae)

7:	Swollen nodes, often hollow twigs

Iresine and Pfaffia (Amaranthaceae)

8:	Jointed, swollen nodes and resin oozing from concentric rings in stem

Gnetum (Gnetaceae) - a gymnosperm!

2:	Leaves Compound

More than one leaflet per node

1:	Leaves Alternate

1 per node

1:	Leaves pinnate compound

With a single, straight rachis

1:	Cylindrical pulvinus and pulvinulus

1:	Green-bean odor

Fabaceae

Very common - biggest family of trees

2:	Treelets or lianas with subopposite leaflets and no odor. Never become big trees

Connaraceae

Much less common

2:	Leaves with odor

1:	Leaves with garlicish odor, often near beaches

Cedrela (Meliaceae)

2:	Canned meat odor (!)

Roupala montana (Proteaceae)

rare at EBCC. But very cool. look for it!

3:	Green-bean odor, and cylindrical pulvinus

Fabaceae

Watch for Picramnia (Simaroubaceae) which is simlar, but with very bitter taste and leaflets that are smaller near the base

4:	Citrus odor, spines on trunk, and punctate leaves

Zanthoxylum (Rutaceae)

5:	Incense-like odor, leaves with distinctly flexed petiolule apices

Protium (Burseraceae)

There are other genera of Burseraceae, and the closely related Anacardiaceae are rare at EBCC. Most have the nice incense odor. Protium odors can also be like dill, or carrots.

Latex

1:	Liana with whitish latex

Sapindaceae

Sapindaceae trees do NOT have latex

Red latex

Dussia, Machaerium, Pterocarpus, Swartzia, Dialium (Fabaceae)

4:	Even-pinnate leaves

Even numbers of leaflets, and usually strictly opposite to each other.

1:	Cup-like glands between all leaflets, often with winged rachis

Inga (Fabaceae)

2:	Raised gland between leaflets

Cassia (Fabaceae)

3:	Terminal "bud" at tip of rachis

Guarea (Meliaceae)

Guarea is really odd and unique - it can make new leaflets whenever, without making a new leaf. very common!

4:	Leaves with alternate leaflets, and aborted rachis tip sticking out beyond terminal leaflet

Sapindaceae

5:	Winged rachis

1:	And green-been odor

Inga, Swartzia, Dypterix micrantha (Fabaceae)

2:	And terminal "bud" at tip of rachis

Guarea pterorachis (Meliaceae)

rare in floodplain

3:	Almost-alternate even-pinnate leaflets

Sapindus saponaria (Sapindaceae)

rare

4:	Spiny vine - prickles on stem and leaves

Solanum viridipes (Solanaceae)

6:	Additional tricky groups

1:	Terminal "bud" at rachis tip

Guarea (Meliaceae)

2:	Leaves with naked rachis apex

Sapindaceae

3:	5-9 odd-pinate leaves, leaflets often alternate, very common

Trichilia (Meliaceae)

Watch also for Tapirira guianensis. It can have a faint mango-like odor, according to Gentry. Basically, it looks like a Trichilia with too many leaflets.

4:	Very bitter taste

Simaroubaceae

Chew on a twig. (make sure it's not an anacard first!)

5:	Liana with paired stipular spines and often red latex

Machaerium (Fabaceae)

6:	Thin, asymmetric serrate leaflets, glands on the rachis between leaflets

Huertea glandulosa (Staphylaceae)

2:	Leaves palmately compound

More than three leaflets arising from the petiole apex

Trees

1:	Malvalean pulvinus at petiole apex, often with spines on the swollen thick trunks

Bombacaceae

2:	Spines on the trunk, milky latex, early successional areas

Jacaratia digitata (Caricaceae)

3:	Stilt roots, conical terminal stipule

Cecropia sciadophylla (Moraceae)

4:	Treelet with cuneate-based leaves

Herrania (Sterculiaceae)

5:	Leaves serrate

Cochlospermum orinococense (Cochlospermaceae)

rare

Vines

Mostly atypical members of simple-leaved taxa - see simple, alternate-leaved vines

3:	Leaves 3-foliate

Mostly variants from pinnately-compound taxa

Trees

1:	Toothed margins, sometimes teeth of two sizes

Allophylus (Sapindaceae)

2:	Spines on trunk or twigs, glands on between leaflets, entire

Erythrina (Fabaceae)

Early successional, mostly

3:	Lots of white latex, mostly in uplands

Hevea (Euphorbiaceae)

very rare in floodplain

4:	Punctations, citrus odor

Rutaceae

Rare in floodplain

2:	Vines and Lianas

1:	Tendrils present

1:	Tendril opposite to leaf base

Cissus (Vitaceae)

2:	Spirally coiled tendril at right angle to leaf base

Cucurbitaceae

3:	Coarsely serrate, inflorescence-derived tendril

Thinouia and relatives (Sapindaceae)

2:	Tendrils absent

1:	Cylindrical pulvini and green-bean odor

Fabaceae

Biggest group of 3-foliate alternate climbers

2:	Treelets or lianas with subopposite leaflets and no odor

Connaraceae

Much less common

4:	Leaves bipinnate or more complex

1:	Cylindrical pulvinus, and often with spines on rachis, twig, or trunk

Fabaceae

2:	Vines and lianas with angled stems, and often milky latex

Sapindaceae (mostly Serjania)

3:	Lianas with tendrils opposite the leaf base

Cissus (Vitaceae)

2:	Leaves Opposite

2 or more per node

1:	Leaves palmately compound

More than three leaflets arising from the petiole apex

a1:	Leaflets tapering onto indistinct petioles, bark tan and thin

Vitex (Verbenaceae)

2:	Leaflet bases rounded or cuneate, frequently with pubescence of stellate trichomes or lepidote scales

Tabebuia (Bignoniaceae)

Rare - mostly in uplands

2:	Leaves 3-foliate

Trees

1:	Leaflets serrate, with terminal stipule

Caryocar (Caryocaraceae)

Rare, mostly in uplands

2:	Hollowed out petiole base with dorsal projection

Metrodorea (Rutaceae)

Rare, only in uplands

Lianas.

1:	Unique terminal leaflet has been transformed into a tendril

Bignoniaceae

Very common - the biggest family of lianas

2:	Like above, but stems deeply ribbed, no tendrils, but petioles can twine

Clematis (Ranunculaceae)

3:	Leaves pinnate compound

With a single, straight rachis

1:	Tree: Leaves glabrous, serrate, and on jointed rachis

Turpinia occidentalis (Staphylaceae)

Liana

Clematis (Ranunculaceae)

Rare

4:	Leaves bipinnate

1:	Gap tree in uplands, serrate

Jacaranda (Bignoniaceae)