pronounced: kas-SITH0uh fill-if-FOR-miss
I think that the word Cassytha is derived from the Greek κασσυω (kassyo), to stitch like a shoemaker. I have also seen claims that it is derived from an Aramaic word kesatha, a tangled wisp of hair, but I have not been able to verify this. Filiformis is from the Latin filum, a thread, and forma, a shape.
We have two species of this genus on Magnetic Island; this one is smooth-stemmed, and the other, Cassytha pubescens, has hairy stems. One of the plants photographed is near the Rocky Bay lookout on the Nelly Bay – Picnic Bay road, and the other directly behing the frontal dunes in Horseshoe Bay. Cassytha filiformis is pan-tropical, whereas Cassytha pubescens is found only in Australia..
Cassytha species are parasitic vines with small haustoria that penetrate the epidermis and withdraw nutrients from the host plant. It does not seem particular as to host plant: it will establish itself over anything growing near it, the same plant spreading over a number of different hosts. It spreads through the tops of trees and bushes forming long festoons of greenish yellow vines. The individual stems, which are copiously branched, range from 1 to 3 mm in diameter, and may grow to a length of about 6 m. The stems contain chlorophyll. The leaves are reduced to minute scales, in Cassytha filiformis only about 1 mm long, most easily seen near the tips of the stems.
The bisexual flowers, borne the year round, are sessile and few in spicate inflorescences 1 (sometimes 2) cm long, each one subtended by an ovate bract and 2 ovate bracteoles, those with ciliolate tips. The tepals are glabrous, strongly unequal, the outer 3 ovate (about 1 mm long) and the inner 3 elliptic (about 2.5 mm long), their tips incurved. The ovary is globose. The floral tube continues to grow after flowering, and encloses the fruits, that are about the size of large peas; dried floral parts persist in the fruiting stage.
The fruits are green or orange-red on maturing, rarely white. They usually dry to black.
Cassytha filiformis is, depending on your point of view, either a blessing or a curse. Hawaiians treasure it for its traditional use as an ornament, and use it in the plaiting of leis. Many traditional societies value it for a wide range of healing applications. It is a food plant not only for birds, but sometimes for humans. In some places it is used for lashing together parts of native huts, particularly in thatched roofs. Experiments have been made to use it as a biological control for invasive species. From the other point of view it is a pestiferous plant able both to smother and to transmit infectious diseases to other plants. It can parasitize plants of agricultural and economic value, both indigenous and introduced. Among crops that it infests, particularly in Hawaii, are fruit plants such as citrus, mango, cloves, nutmeg and avocado. There it commonly occurs on native or naturalized woody coastal hosts such as Tournefortia argentea (tree heliotrope), Scaevola taccada (sea fanflower), Metrosideros polymorpha (ʻōhiʻa lehua, the most common native tree of the Hawaiian islands), Morinda citrifolia (noni), and Pandanus sp. (screw pine).
This is a food plant for several caterpillars, including those of the butterflies Botched Blue Candalides acasta and Small Dusky Blue Candalides erinus, and the Whistling Moth Hecatesia fenestrata.
