Bowenia Overview

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The genus Bowenia Hook ex Hook. f. belongs to the tribe ZAMIEAE Reichenb. in the family ZAMIACEAE Richenb. It consists of two endemic species confined to Queensland.

Bowenia is unique amongst cycads in that it has decompound leaves, all other genera are simply pinnate although some lobing or dividing of the leaflets may be present. It is this very striking and unusual feature of Bowenia which makes it highly distinctive. It also shows some advanced features and its affinities are not with other Australian Zamiaceae but apparently with the New World genus Zamia.

The two species of Bowenia are morphologically similar but cannot be confused. They are also members of different plant communities and in only one location do they occur within close proximity of each other.

Bowenia spectabilis Hook. ex Hook. f. is the type of species of the genus (1863) and is confined to the moist rainforests of north-eastern Queensland from about Cooktown south to the rainforest limit in Rockingham Bay. It extends inland some 45-50 km. and up to at least 700 m. altitude. The habitat is usually the shaded rainforest floor but quite healthy plants can be found on rock faces near waterfalls and along creek banks. It seems to be requiring of a permanently moist soil and a high humidity. Soil type does not appear to be highly important however the plants can be quite abundant on red volcanic loams.

B. serrulata (W. Bull) Chamberlain (1912) was initially thought to be a variety of the type species. For a full treatment of the synonymy involved see Johnson (1959). This species is more characteristic of moist sclerophyllous forest but occasionally enters into rainforest. It has three main areas of occurrence, two of which are not widely understood and one of which is not verified by the present author. The main occurrence is in the region directly north of the Tropic of Capricorn from about Yeppoon to St. Lawrence and mainly on the coastal flats and hills in moist open forests. The second occurrences in the Casuarina dominated scrubs around Lake Tinaroo near Atherton where it grows next to B. spectabilis but apparently does not hybridize with it. The population there is considerable. The third occurrence is quite a good way farther north in the Mclllwraith Range on northern Cape York Peninsula. The present author has not seen this population and knows nothing of the habitat associations there, the information comes by way of C.S.I.R.O. collectors.

It would seem from the above that B. serrulata is far more widespread and common than most people assume. Its occurrence on the northern Peninsula is quite amazing considering the distinctive flora of that region which has greater affinities with Papua than with southern Cape York Peninsula. It would be very fascinating and exciting if Lepidozamia were to be found in that region where as far as it is known only Cycas occurs.

Bowenias do very well in cultivation and can in north Queensland grow into fertile plants in 5 years from seed. With this knowledge it is surprising that they are not more commonly cultivated but perhaps that is fortunate, for the nurseryman is more apt to be lazy and remove plants from the wild rather than raise seed.

As a container grown specimen, Bowenia is one of the most pleasing and convenient. Both species can tolerate very low light intensities and can be grown indoors permanently, although B. serrulata tends to need more light when growing new leaves so that they do not become weak. The present author has grown both species successfully in Weipa indicating that all year round high temperatures are not detrimental.

The leaves are quite durable and the natural gloss makes them a handsome feature in the home. Quite large plants can be grown in smallish containers. A plant with leaves over 1 m. high can be easily grown in a 250 mm. pot. A rich loamy soil consisting of some humus or rotted manure is suitable. Experiment has shown that reporting stimulates new growth. The old soil can be completely washed away with a garden hose and the plant re-potted in the same container. A small amount of water soluble fertilizer during growth is beneficial.

Scale insects can be a problem if the plants are neglected. Usually the scales are tended by ants, which introduce them and obtain a secretion from them. The scale can be safely wiped off the leaves and the soil drenched with a Pyrethrum insecticide to kill the ants and any root infestation of scale. Regular inspection for re infestation will need to be carried out after such treatment.

Bowenia can produce cones in a container. The females are quite low and can develop unnoticed if leaf litter covers the soil, but the tall male cones with their ghostly white colour and elegant form are extremely decorative and make excellent photographic subjects. Cones develop during cool months but occasionally develop in the summer. Should one have a male and female in cone at the same time hand pollination can be carried out with great success.

As a garden plant Bowenia needs shelter from hot sun and drying winds but is not demanding and will regularly produce new leaves. B. serrulata can take more sun and the new growth as a result has a coppery colour which is very attractive.

Bowenia is a unique and valuable genus and is part of our floral heritage, let us hope that the future will see it increase and not diminish.

The main difference between the species are fairly reliable and can be set out as follows:

Character (see below) B.spectabilis B. serrulata
Leaf Height up to 2m. up to 1.2m.
Leafletform lanceolate rhomboid
Rachillae +/- drooping semi-erect
Leaf Width up to 1.5m. up to 1 m.
Plant Form solitary clumping
Leaflet Marginentire or rarely
preamorse
finely serrate

These characters are fairly uniform but some deviation can be expected under various circumstances. A false-clumping effect in B. spectabilis can arrive through the germination and successful establishment of several seeds together or rarely very old plants divide, particularly on volcanic soils.

References:

Johnson L.A.S. The Families of Cycads and The Zamiaceae of Australia, Proceedings of the Society Of New South Wales, 1959, Vol. Ixxxiv, part 1.

Contributed by:

Robert Tucker, from PALMS & CYCADS No. 25, Oct-Dec 1989.