Amy Sellwood, of Balclutha Primary School, asks :-
Are three sycamore seeds stuck together usual?
Janice Lord, a botanist at the University of Otago, responded.
No, it is unusual to see three sycamore seeds stuck together. Sycamore is in the maple family and maple fruits are usually what is called a “double samara”, which is a pair of winged, joined seeds. Winged seeds as a dispersal mechanism are often a feature of rapidly growing trees that specialise in colonising gaps or disturbed edges of forests. When released from a height, the seeds are able to catch air currents and potentially reach new gaps or disturbed areas.
Dispersing seeds like this is relatively cheap as the plant hasn’t had to invest in sugary pulp to attract animals to eat the seeds. When seeds are cheap to produce, the plant can afford to make more of them, which is an advantage when gaps in the forest might be few and far between.
Sycamore is a invasive tree, particularly in urban bush remnants, largely due to its rapid growth and highly effective seed dispersal. Native trees which use this dispersal mechanism include Dodonea (akeake) and Hoheria (lacebark). The ability of the seeds to travel depends on the area of the wing in relation to the weight of the seed. Paired seeds are likely to be better balanced and so keep the seed in the air for longer. If you still have your “triple samara” you could conduct your own scientific experiment to see how long it stays in the air and how far it travels compared to a normal double samara and a single samara (split a double samara in half). Then you could compare distance travelled or time aloft with the wing area to seed weight ratios of each type of samara. Your triple samara may turn out to be a mutant super flyer (or a lead balloon)!