Description Of Commercially Available Species
- adelae Erect with narrow lanceolate leaves, 4-10 in. (10-25 cm) long, crowded on a short stem. Scapes 1-3 with numerous red flowers on each. (Photo 4-13)
- burkeana A rosette with oval leaves. The petiole is narrow, up to 0.8 in. (2 cm) long, broadening abruptly into the blade which is about 0.4 in. (1 cm) long. Two to 12 white or pink flowers are borne on each scape.
- burmannii A basal rosette with reddish leaves having unusually long tentacles. The circular blade is about 0.47 in. (12 mm) long and 0.43 in. wide narrowing to a short flat petiole. There are 1-5 scapes per plant with 3-14 white flowers on each.
- peltata Described in Temperate Sundew section.
- prolifera A basal rosette that is semi-erect. Petiole is narrow, 2 in. (5 cm) long attached to a kidney-shaped blade 0.6 in. (1.5 cm) long and 0.8 in. (2 cm) wide. The scapes (1-3) bear 2-6 pink to red flowers and tend to trail on the soil surface. There is a vegetive bud at the end of the scape that will develop into a plant.
- schizandra Large leaves form a rosette from which a short scape bearing 2-6 white flowers emerges. The leaf petiole is very short while the blade can be up to 5 in. (13 cm) long and 2.5 in. (6 cm) wide with or without a notch on the end or apex of the blade.
- spathulata Leaves whose outline varies from spoon-shape to wedge-shape form a basal rosette. This species is widespread geographically and the shape of the leaf varies in different areas resulting in plants that appear to be distinct species. The group is referred to as the Spathulata Complex. Petioles are up to 1 in. (2.5 cm) long, gradually widening to the blade that can be up to 0.5 in. (1.3 cm) long. One to 15 white or pink flowers are borne on each scape which can number from 1 to 3.
CULTURAL INFORMATION Planting Media
Sphagnum peat moss, sphagnum moss (living or dead), one part sphagnum peat moss to one part perlite, or one part sand and various mixtures of sphagnum moss and sphagnum peat moss.
Summer: 70-95°F (21-35°C). Winter: 60-70°F (16-21°C). Tropical Drosera can be grown year around at the summer temperatures given above, but for most, a lower winter temperature insures more uniform flowering in the spring.
- peltata dies back during the summer leaving a viable tuber in the soil and resumes active growth during the winter. The other tropical Drosera, except the annuals, usually grow very little, if any, during the winter season.
- burmannii and D. indica are annuals. To maintain a supply of plants, their seed must be collected and sown each year. Allowing the seed to fall to the surface of the soil in the pot and regrow in the same soil is satisfactory for a few years, but the soil should be changed every 3 years or sooner if growth is not as vigorous as before and/or if plant pests appear.
Allowing the seed to drop and germinate at the base of the plant will result in a very thick crop of young plants which must be thinned to avoid an environment conducive to fungal infections. It is usually efficacious to collect the seed and sow the amount required for your needs and save the rest.
D. petiolaris should have reduced water during the summer. (Photo 4-14) The soil should be much drier during the summer than winter, but not thoroughly dry. During the winter, its normal growth period, the temperature should be in the summer range and the soil should be wet. The other tropical Drosera species usually cease to form new leaves during the winter.
Water & Humidity
All species require high humidity and wet medium during the growing season. The medium should be drier when they are not actively growing.
All of the tropical Drosera grow in bright light in their native habitat save for D. adelae, D. prolifera and D. schizandra which grow in shaded areas. We have grown D. prolifera and D. adelae in very bright light without any apparent harm, but the leaves are smaller than when grown in subdued light. We have found that D. schizandra grows best in weaker light. When under artificial light use 1000 foot candles with all species except for D. schizandra which should be at about 750 foot candles. Photoperiod: Growing season about 14 hours, dormant season about 11 hours.
The only pests we have had are aphids and fungus. See Chapter 8 for treatment. Feeding
See Chapter 7 for feeding instructions. Miscellaneous
D. schizandra grows best in living sphagnum moss and with a relatively uniform temperature. It apparently requires extremely high humidity, as it does not grow well in the greenhouse in which we grow our Nepenthes. We provide a higher humidity for D. schizandra plants by planting them in living sphagnum moss and placing them in sealed plastic bags which are then kept in the Nepenthes greenhouse. The result is much better growth. The easier species to grow in this group include D. adelae, D. burmannii, D. prolifera, and D. spathulata.
To our knowledge D. burmannii, D. indica, D. burkeana, D. affinis, D. spathulata, D. madagascariensis, D. pilosa, D. peltata, and D. banksii will flower, self-pollinate, and produce viable seed under cultivation. Although our D. adelae and D. prolifera flower profusely, they have never set seed. Cross-pollination efforts have not been successful. D. petiolaris and D. schizandra flower occasionally but neither one has produced seed. Sow seed on the surface of the planting medium, maintain a high humidity and bright light with a temperature range of 70-95°F (21-35°C).
- Leaf cuttings: All the species except D. burmannii, D. indica, and D. spathulata will produce new plants from leaf cuttings. Remove the entire leaf including the petiole, place it on damp planting medium, preferably living sphagnum moss, keep the humidity high, the light bright and at a temperature from 70-85°F (21-29°C). Once new plants are fully rooted they can be transplanted.
- Stolons: D. prolifera produces scapes that sometimes bear flowers, while at other times produce plants. To further complicate matters, the same scapes sometimes produce both flowers and plantlets. (Fig. 4-6) When the plantlets produce a root system they can be severed from the mother plant and transplanted. (Photo 4-15) We have
Bcr<»v»>- j found it is best to sever the plantlet from the mother plant about 1 month in advance of transplanting it. The latter technique helps insure against losing the plantlet when transplanting.
- Root cuttings: D. adelae, D. prolifera, D. schizandra, and D. spathulata will reproduce from root cuttings. Select fleshy (thicker) roots, cut them into 1-2 in. (2.5-5 cm) lengths and follow the procedure given for leaf cuttings. This procedure may work with other species in this group also. (Fig. 4-7)
- Decapitation: The aerial part of the plant is cut away from the root system just below the crown. The removed part is treated as a cutting would be and will develop roots in 1-2 months. The roots left in the medium will produce new plants. All species that can be propagated by root cuttings are amenable to this procedure.
- Stem cuttings: D. adelae, D. affinis, and D. pilosa can be propagated by stem cuttings. Remove 2-3 in. (5-8 cm) from the top of the plant and place the removed section in sphagnum moss. Keep the cutting under the same conditions as prescribed for leaf cuttings. The remaining portion of the mother plant will continue to grow.
- Fig. 4-6 Drosera prolifera plant. Leaves form a rosette. Flower scapes sometimes bear flowers or plantlets or both.
- Fig. 4-7 Plantlets of Drosera adale produced by means of root cutting.
Drosophyllum's ability to capture insects was well known for hundreds of years before any thought was given to its possible carnivorous nature. Darwin investigated Drosophyllum for carnivory, but it was A. Quintanilha of Portugal who did the critical study of Drosophyllum, verifying that it secreted a digestive enzyme that effected digestion without bacterial assistance. The first part of the name Drosophyllum is derived from the Greek drosos, meaning dew, and phyllum is from the Greek phylon for race or tribe.
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