Markea viridiflora

This plant grows in the cloud forest of Brazil. It is seldom seen in cultivation and has a similar growth habit as the Solandra of which it is a relative. The Markea can grow to a height of 2 metres and flowers easily. The flowers are green with a reddish tint on the outside. They are 9 cm long, 10 cm if you include the protruding stems. The flower is bell-shaped and 3 cm in diameter. The tips of the petals fold back. The leaves are 13 x 4 cm and are not positioned opposite each other, contrary to the position of the leaves in other plants which tend to grow in opposite pairs. The stems have a reddish tint.

There are a few other species of Markea, which I have not seen myself, but four are shown on the Cornell University website (see here). The plant can flower from cuttings after about 6 months as the one in the photo did. That particular plant was 23 cm high when I took the photo. The flower lasted about 2 weeks and I tried self-pollinating it in the hope to get fruit and seed, but it did not work. The flower dropped off, which may suggest that cross-pollinating is necessary. Unfortunately, I do not have a second plant, so will have to find one.

 

 

Ceropegia galeata

A rare Ceropegia that comes from Maji Ya Chumvi on the Mombassa Road between Voi and Mombassa. It grows in an area that is very hot, reaching temperatures of 40°C. It looks similar to Ceropegia sandersonii with a parachute-like structure. It grows mostly in Acacia shrubs where it gets protection from goats. It also grows in other shrubs and in grass, but it is then more likely to be eaten by the goats.

It can grow up to 2 metres in length and the stems are very similar to those of Ceropegia ampliata with the same small leaves, but the stems are grey in stead of green. The roots are fusiform, that is to say, thick and spindle-like. One specimen was found last year in flower. This year, I searched the same area and after twenty minutes I found one plant with a seedpod from which I collected some seed. I sowed some in my greenhouse and some have been put in tissue-culture to get this species into circulation to collectors. The seed has germinated and the plants are growing reasonably well. Patience, patience ….

Ceropegia galeata seedpod

Ceropegia galeaeta flower (photo taken last year by Rainer Martin)

 

Aristolochia triangularis

Aristolochia is a family of plants with around 400 species that are spread over many parts of the world. They grow as either vines, which can produce many metres of growth, or as herbaceous plants. There are some Aristolochia sorts that have tuberous roots, such as A. fimbriata, but the majority do not. The leaves are heart-shaped and the flowers are not unlike Ceropegias. They are pollinated by flies which are trapped for a day or so and then released to fly to the next flower.

A free-flowering species that is easy to grow, producing many metres of growth in one season, is Aristolochia triangularis. The leaves are large, often hiding the flowers. The seed is produced in small capsules with several seeds in a pod. Propagation is either by cuttings or seed. The seed takes about 2 or 3 weeks to germinate. So far, my plant has not been attacked by any pests or diseases, but I have only grown it for two or three years, so I have no long-term information to give on this point.

The plant occurs naturally in Northern Africa, Western Asia and South-Eastern Europe and may very well be winter-hard in slightly cooler climates, but I have not grown it outside myself, so no guarantees. In the winter, I keep it at 10°C in a greenhouse and only bring it outside when the frost is over.

Aristolochia triangularis

 

Ceropegia meyeri

A very rare tuberous-rooted species that grows in Zimbabwe. The only part of this plant that is actually succulent is the tuber, the rest is non-succulent growth. The stems are thin and hairy, the leaves are heart-shaped without any hairs on. The flowers are pollinated by small flies of various species; size being the important qualification and not the particular species of fly as the plant is pollinated over here by different flies from the ones they have in Zimbabwe. When pollinated, seed horns are formed of about 10 cm. Make sure you catch the seed before it is released, otherwise you will lose it. The seed should be sown within half a year of collecting, preferably earlier, because it has a limited shelf-life. The seeds can germinate within 24 hours if sown under plastic and kept moist. It will form a reasonably-sized tuber and flowers in the first year of growth.
The plant should be kept in a warm greenhouse (minimum 15°C). In the winter the tuber has to be kept dry, otherwise it will rot. The plant prefers an open soil with good drainage.

Ceropegia meyeri is very rare in cultivation, partly because seed is hardly ever available and the plant is not so easy to propagate from cuttings. It is possible to take cuttings, however, but you need a high temperature (25-30°C) and a high humidity. As with most other tuberous-rooted ceropegias, unlike some other caudex plants (e.g. Adenium obesum), a plant grown from cuttings will develop a tuber. The plants climbs through other plants, using them as support.

Ceropegia meyeri

 

Mimosa pudica

Mimosa pudica is commonly called the sensitive plant. The name Mimosa comes from the Greek mimos (to mimic) because when touched, the plant ‘mimics’ animals that shrink away from being touched. The sensitivity of the leaves is a protection against grazing animals; the plant has the capability of feeling the animal approaching through air movement or vibration. Tapping the pot or touching the leaves will have the same effect; they will close up. Once the leaves have folded up, animals ignore them, not just grazing animals, but, for instance, grasshoppers interpret the closing of the leaves as a trap shutting them in and they will jump away. The warmer it is, the quicker the reaction of the leaves. The leaves fold upwards, contrary to those of Biophytum, which close downwards.
The plant originates from South-America, but has now spread over most of the world to all parts where there is no frost and sufficient water. It can be seen growing on the side of the road where it is will stay shorter than in other habitats, because of poor soil conditions. The plant has become a weed in some countries, esp. in Australia, because it does not have any natural (grazing) animals there.
It is a very easy plant to grow from seed; the seed needs to be soaked in water for 24 hours before sowing and then it can be sown under plastic. In about a week or so, germination takes place. To get a nice bushy plant, it is better to sow a few seeds in a plants rather than just one. The plant will flower in the first year producing pink flowers. Rubbing the flowers together, will pollinate them and in this way you can produce your own seed. Although the plant is a perennial, it is normally grown as an annual, because it will grow straggly and untidy if left to grow on. The plant can be grown in full sun without any problem, but do not let it dry out, because once it had dried out, it will not recover again.
It is an ideal plant for children to play with. After closing up, the leaves will reopen after about a quarter of an hour in good weather. The plant suffers no harm being played with in this way, unlike the Venus flytrap which will be killed if forced to close too often.

Mimosa pudica leaves

Mimosa pudica flower and closed-up leaf

 

Lopezia racemosa

This unusual plant is a perennial, but is mostly grown as an annual. It is very easy to grow from seed if sown in February to March. It will already flower in May or June of that same year and will continue flowering till September or October, producing many seed berries which contain 50-100 seeds each. This large seed production (and the risk of it becoming a weed) is also known in another plant, Talinum paniculata. When ripe, the berries turn brown and open on the bottom to release the seed, unlike Talinums which explode, scattering the seed over wide areas.

Lopezia can grow in poor soils where it will remain a reasonably small plant. In richer soils, it will grow much larger, up to a meter high. It is native to Mexico, Salvador and Guatemala and belongs to the family Onagraceae. There are seven species known in these countries, all fairly similar in growth and requirements. L. racemosa is commonly known as the mosquito flower because the flowers resemble a mosquito flying at you.

Lopezia racemosa

 

Gelsemium sempervirens

This plant is commonly known as the yellow jasmine, because it is highly scented. It is a winter-flowering evergreen plant that can climb up to six metres high. It is native to the USA and new in cultivation. The plant can stand cool conditions, even a little bit of frost. It is tuberous-rooted, producing a tap root. The leaves, roots and flowers are poisonous when ingested. Gelsemium is an ideal plant for in the full sun, but it will also grow and flower well in the shade. In the wild, it attracts hummingbirds and swallow-tail butterflies.

The flowers look very similar to those of Adeniums and Pachypodiums, but it is not in the Apocynaceae family, but in the Gelsemiaceae. The plant can be propagated by seed or softwood cuttings. The latter method is more likely to be used because the seed, when ripe, explodes and is thrown all over the greenhouse in a similar way to the seed of ruellias. Two plants are needed for pollination.

As I have not had this plant for very long, I do not yet know which pests might be a problem.

Gelsemium sempervirens

Gelsemium sempervirens

 

Dregea sinensis

Dregeas come from Asia and are evergreen in the wild, but if you keep them in your greenhouse with low winter temperatures, they will lose most of their leaves. They are also known under their synonym Wattakaka sinensis.
It is a climbing plant that will flower every spring with white flowers that have a splash of pink in the centre. They are highly scented, which usually means in these type of plants that they are moth-pollinated. The flowers last for up to a week and resemble hoya flowers. Not surprising as Hoyas and Dregeas are related. Another asclepiad species that has highly scented moth-pollinated flowers is Araujia sericifera, although the flowers on that plants do not resemble Dregea flowers.

Dregea sinensis

As with Hoyas, Dregeas rarely set seed in the greenhouse, but when they do, they form twin-seed horns which will burst open when ripe and can contain up to 50 seeds. The seeds remain viable for up to a year, but it is better to sow them as soon as possible. If you sow them straight away, you will get almost 100% success; if you leave it till 3-6 months, you will get 25-50%; and after a year, you may only get one or two to germinate.
The leaves are heart-shaped and fairly large. It is possible to propagate this plant by cuttings, preferably in the spring. I use cuttings with two nodes, one for the roots and one for the new growth, just as you would do with Hoyas. They can be grown in shade or full sun and will grow outside in the summer. They can have a bit of frost (-2 or 3°C), but it is better to give them some protection.

 

Hoya pallilimba

Before 1994, few Hoya species from Sulawesi were in collections, but in that year a group of Hoya enthousiasts spent three weeks collecting Hoya material on the island. About seventy numbers were collected, but as they were not in flower, some species were collected several times. The plants were brought back to Holland, grown on and brought into flower. One of the species collected was at the time given the number 114, later changed to 8864, and only determined as Hoya pallilimba by Ruurd van Donkelaar and David Kleijn in 2001 (‘Taxonomy and ecology of the Genus Hoya’ in Blumea, 46/3, pp. 457-483). The pallilimba was found by the Ranu River in the Morowali reserve and is a species that grows in association with ants. The ants (genus Tetramorium) take the seed into holes in branches to store as a food supply; the seeds that are not eaten will germinate and grow from the hole. The plant is not solely dependent on the ants; seeds that drop into leaf litter in the fork of branches will also germinate.
Pallilimba is a hanging species that is not very free-flowering. It also has to be reasonably large before it will flower. The plant itself when not in flower is very similar to two other species on the island, Hoya brevialata and Hoya myrmecopa. It is a lot easier to tell them apart, when the plants are in flower. Brevialata has much larger flowers and can be red or white. Myrmecopa has flowers that hang down as buds but which will stand upright when open. Pallilimba flowers are smaller and always reddish in colour.
The plant is reasonably easy in cultivation and can reach a length of 1.50 mtr. It is best grown in a hanging pot to give the stems enough room. It is easily propagated from cuttings; in the summer they will root in about 10-12 weeks. The plant requires higher temperatures than many of the other hoyas, around 20°C minimum.

Hoya pallilimba GPS8864

 

Cibirhiza dhofarensis

This very rare Asclepiad and one of only two endemic species from the Dhofar region of Oman, the other being a Dhofaria macleishii (of the Capparaceae family). It is extremely drought tolerant and slow growing. It is an ideal plant for a small collection as it grows very slowly. I have had mine for about 3-4 years now and it has only grown by 4 centimeters in that period. Not suprisingly, it does appreciate warm temperatures, at least 20°C. Despite the fact that it grows in the full sun in the wild, my experience with this plant has shown that it can be grown in the shade without any problem.

It will also flower well, producing up to ten flowers successively in October-November. The flowers are about half a centimeter in diameter and stay open for two or three days. On my plant, they are produced on the new growth at the end of the stem, but in older plants with more growth, they grow in the leaf axils. You can see a picture of a dried specimen here. The few leaves the plant produces at the end of the stem, drop off before the flowers appear. The leaves you see growing in the picture are from a different plant, a Dorstenia foetida.

The plant was named Cibirhiza dhofarensis by Peter Bruyns, but is also known as Cibirhiza dhofarica. Cibirhizas are closely related to Fockea, a well-known species of that genus being Fockea edulis. The tuber of the Cibirhiza is supposed to be edible, but I have not tried it, because I only have one plant and it would be a shame to destroy it.

Cibirhiza dhofarensis

Cibirhiza dhofarensis