On this first page, we study the type of begonia (terrestrial or epiphytic), its habit (rhizomatous, climber, upright stem, etc.), the consistency of the stems, its longevity (annual or perennial), and the presence or absence of tubers and bulbils.
1. Substrate
Terrestrial plant
Said of a plant that grows on the ground.
- on the forest floor
- B. elatostemmoides Hooker f. / section Filicibegonia / Gabon
- B. maynensis A. De Candolle / section Knesebeckia / Ecuador – Peru
- on the ground of a mountain meadow
- B. froebelii A. De Candolle / section Eupetalum / Ecuador
- or on rocks (saxicolous plant)
- B. ankaranensis Humbert / section Quadrilobaria / Madagascar / on limestone
- B. keraudreniae Bosser / section Erminea / Madagascar / on gneiss
- B. mananjebensis Humbert / section Quadrilobaria / Madagascar / on gneiss and lava
Epiphytic plant
Plant which most often grows on another plant, usually a tree, without being a parasite. When the plant starts growing, it may start from the ground (from seed or from a fallen leaf), then climb, cling to a tree and free itself from the ground; it may also develop on its support, with no link to the ground.
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- B. longipetiolata Gilg / section Tetraphila / Tropical Africa / epiphytic on a trunk
- B. quadrialata Warburg subsp. quadrialata / section Loasibegonia / Tropical Africa / also epiphytic on a trunk
Some species have terrestrial individuals and epiphytic or saxicolous ones.
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- B. Madagascar sp. / section Erminea / Madagascar (Makira Forest) / some plants of this tuberous species grow on the ground, on rocks or on trunks
2. Longevity
Annual plant
A plant with a short life, often a single season (the rainy season): with these begonias, we can see all stages simultaneously: adult plants, plantlets, fruits with seeds and seedlings.
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- B. humilis Dryander / section Doratometra / north-west South America / annual Begonia
Perennial plant
A plant that lives for several years; most plants of the genus Begonia are perennial.
3. Stem
Herbaceous stem
Having the consistency of a herb.
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- B. roxburghii A de Candolle / section Sphenanthera / India – Burma / plant with herbaceous upright stems
- B. hemsleyana JD Hooker / section Platycentrum / China / plant with herbaceous upright stems
Woody stem (at least at base or suffrutescent)
Having the consistency of wood; many begonias have herbaceous stems that are woody at the base.
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- B. henrilaportei D. Scherberich & J. Duruisseau / section Nerviplacentaria / Madagascar / woody stems at base
- B. ferruginea Linneaus / section Casparaya / Colombia / sarmentose plant, a climber that grows up to 3 or 4 m high by clinging to neighbouring shrubs
Plant without an aerial stem (or acaulescent)
This is the case for some tuberous begonias; the leaves then grow directly from the tuber.
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- B. ambodiforahensis D. Scherberich & J. Duruisseau/ section Erminea / Madagascar (Masoala) / acaulescent saxicolous begonia
Bulging stem at base (caudex)
Plant with an upright stem bulging at base as a caudex.
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- B. aconitifolia A. de Candolle / section Knesbeckia / Brazil / begonia with a caudex (in cultivation)
- B. dregei Otto & Dietrich / section Augustia / South Africa / begonia with a caudex (in cultivation)
4. Type
Rhizomatous plant
Plant with a rhizome, underground or creeping, from which roots, aerial stems or leaves grow.
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- B. rex Putzeys / section Platycentrum / India (Himalaya Piedmont) / rhizomatous species
- B. vittariifolia N. Hallé / section Scutobegonia / Gabon / rhizomatous, saxicolous
- B. carrieae Schlechtendal & Chamisso / section Gireoudia / from Mexico to Colombia / rhizomatous (in cultivation)
Upright stem
The plant produces stems, sometimes thick, rising from the ground, upright and bearing the leaves.
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- B. carolineifolia Regel / section Gireoudia / Mexico – Guatemala (in cultivation)
- B. sericoneura Liebmann / section Gireoudia / Central America and north-west South America / on a roadside bank in Colombia
Rhizomatous plant, with upright stems from the rhizome
The stems with leaves start from the rhizome
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- B. buddleiifolia Linden / section Pilderia / from Venezuela to Peru
- B. tengchiana Ch.I-Peng & Y.K. Chen / section Diploclinium / Taiwan
Climber
Sarmentous plant sometimes woody, often climbing, sometimes creeping on ground ; it is not an epiphytic begonia and always grows from the ground.
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- B. lyallii var. lyallii A. de Candolle / section Nerviplacentaria / Madagascar / may spread over 4 or 5 m
- B. lyallii var. lyallii A de Candolle f. masoalensis Aymonin / section Nerviplacentaria / Madagascar (Masoala) / creeper
- B. Ecuador sp. / section Gobenia / climbing species on mossy trunks at an altitude of 3000 m
- B. glabra Aublet / section Wageneria / Central America and South America / creeper on trunks and rocks.
Tuberous plant
Plant with a tuber or a swollen (tuberous) root, perennial and serving as a reserve; many begonias are tuberous; they may be terrestrial, saxicolous or epiphytic.
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- B. aequatorialis L.B. Smith & B.G. Schubert / section Eupetalum / Ecuador / Andean tuberous begonia at high altitude
- B. erminea L’Héritier / section Erminea / Madagascar / tuberous saxicolous
- B. betsimisaraka Humbert / section Erminea / Madagascar / tuberous on ground or epiphytic on trees
- B. sambiranensis Humbert / section Quadrilobaria / Madagascar / tuberous saxicolous
Bulbils
Small plant organ resembling a small bulb, forming on the stems, often at the leaf axils; they self-sow and produce new plants. Bulbils are most often found on tuberous plants; they appear when the plant is about to go dormant.
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- B. grandis Dryander / section Diploclinium/ China Japan / bulbils appear at the insertion of a petiole
- B. sutherlandii JD Hooker / section Augustia / East and South Africa / also produces bulbils before going dormant
Bulbils are sometimes found on annual plants.
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- B. wakefieldii Gilg / section Augustia / East Africa / annual plant that produces bulbils before dying (and sometimes a tuber before the aerial part disappears)
