Keys to Dicotyledon Families
KEY 4. EPIPHYTIC MAGNOLIOPSIDA
This key includes all those dicotyledons that grow upon other plants, including the hemiparasitic Loranthaceae and Viscaceae. Some plants, such as species of Ficus, may start as epiphytes but later develop into free standing trees. The roots of others may (hemiepiphtyes) or may not reach the ground during part of their life cycle. See definitions of epiphyte and hemiepiphyte in part 1, page 11.
| 1. Plants herbaceous. | 2 |
| 1. Plants woody. | 5 |
2. Flowers apetalous; ovary unilocular, with single ovule. |
Piperaceae (Peperomia) |
2. Flowers not apetalous; ovary with >1 ovule per locule. |
3 |
| 3. Plants without apparent leaves, the stems fleshy and green. | Cactaceae |
| 3. Plants with leaves, the stems not fleshy and green. | 4 |
4. Leaves alternate; stipules conspicuous. Flowers unisexual; corolla not fused into tube (choripetalous); ovary inferior, winged. Seeds dust-like. |
Begoniaceae |
4. Leaves opposite; stipules absent. Flowers bisexual; corolla fused into tube (gamopetalous); ovary superior, not winged. Seeds not dust-like. |
Gesneriaceae |
| 5. Flowers subtended by modified, nectar-producing bracts. | Marcgraviaceae |
| 5. Flowers not subtended by modified, nectar-producing bracts. | 6 |
6. Leaves simple and alternate. |
7 |
6. Leaves simple and opposite (sometimes some alternate leaves also present on same stems as opposite leaves in some Loranthaceae). |
11 |
| 7. Plants with exudate. Flowers located in special branch ends (figs or synconia). | Moraceae (Ficus spp.) |
| 7. Plants without exudate. Flowers not located in special branch ends. | 8 |
8. Inflorescences not in heads or congested umbels. Flowers >5 mm long; perianth biseriate, the petals fused into tube. |
9 |
8. Inflorescences in heads or congested umbels. Flowers < 5 mm long; perianth uniseriate, or if biseriate, the petals not fused into tube. |
10 |
| 9. Corolla tube >50 mm long; anthers with lateral dehiscence; ovary superior. | Solanaceae (Markea) |
| 9. Corolla tube <30 mm long; anthers with poricidal dehiscence; ovary inferior. | Ericaceae |
10. Petioles unequal in length. Perianth biseriate; ovary inferior, multilocular; placentation axile. Fruits not yellow-orange, not surrounded by fleshy perianth (the fruit itself may be fleshy). |
Araliaceae (Oreopanax) |
10. Petioles not markedly unequal in length. Perianth uniseriate; ovary superior, unilocular; placentation basal. Fruits yellow-orange, surrounded by fleshy perianth. |
Cecropiaceae (Coussapoa) |
| 11. Base of plant penetrating tissue of host (hemiparasite). | 12 |
| 11. Base of plant not penetrating tissue of host. | 13 |
12. Flowers usually >3 mm long (flowers of Oryctanthus florentus may be larger), in some species very large and showy, bisexual; perianth 6 merous; calyx (as small, rim-like calyculus) and corolla present. Inflorescences with pedicellate flowers. |
Loranthaceae |
12. Flowers <3 mm long, never showy, unisexual; perianth 3-4 merous, only one perianth whorl present. Inflorescences with sessile flowers. |
Viscaceae |
| 13. Plants with exudate, this often yellow. Flowers unisexual, with sticky exudate; stamens >10. | Clusiaceae |
| 13. Plants without exudate. Flowers bisexual, without sticky exudate; stamens less than or equal to 10. | 14 |
14. Leaves with interpetiolar stipules. Ovary inferior; petals fused into tube. |
Rubiaceae |
14. Leaves without interpetiolar stipules. Ovary inferior or superior; petals free if ovary inferior, fused into tube if ovary superior. |
15 |
| 15. Leaf blades with arcuate secondary veins and characteristic ladder-like tertiary veins between the secondary veins. Flowers with free petals; stamens 10; ovary bilocular; placentation axile. | Melastomataceae |
| 15. Leaf blades with pinnate venation and reticulate tertiary veins. Flowers with petals fused into tube; stamens 4; ovary unilocular; placentation parietal. | Gesneriaceae |
Key to Keys | Key 1. Achlorophyllous Magnoliopsida | Key 2. Herbaceous Terrestrial or Aquatic Magnoliopsida | Key 3. Climbing Magnoliopsida | Key 4. Epiphytic Magnoliopsida | Key 5. Tree Magnoliopsida | Key 6. Shrub Magnoliopsida