The Island of the Colorblind

In his Useful Plants of the Island of Guam Safford has much to say about Cycas circinalis  – its role in Chamorro culture, its use as food; but ‘its chief interest,’ he adds (one remembers that he is a botanist here), ‘lies in the structure of its inflorescence and the manner of its fructification.’ At this point he cannot suppress a special enthusiasm and excitement. He describes how the pollen settles on the naked ovules and sends a tube down into them, within which the male germ cells, the spermato-zooids, are produced. The mature spermatozooids are ‘the largest known to occur in any animal or plant. They are even visible to the naked eye.’ He goes on to describe how the spermatozooids, which are motile, powered by cilia, enter the egg cell and fuse with it totally, ‘cytoplasm with cytoplasm, nucleus with nucleus.’

These observations were quite new at the time he was writing; for though cycads had been described by Europeans in the seventeenth century, there had been much confusion as to their origins and place in the vegetable kingdom. It was only the discovery of their motile spermatozooids, by Japanese botanists in 1896, that afforded the first absolutely clear evidence of their kinship (and thus of their whole group, the gymnosperms) with ferns and other ‘lower’ spore-bearing plants (which also have motile spermatozooids). The importance of these discoveries, made only a few years before he wrote, is strong and fresh for Safford, and enriches his account with a feeling of intellectual fervor. Longing to see this visible act of fecundation for myself, I pulled out my hand lens and peered into the male cone, then into the notched ovules, as if the whole drama might be enacted before my eyes.

Tommy and Beata seemed amused by my barmy enthusiasm, and burst out laughing – for them, basically, cycads are food. Their interest is not in the male plant, its pollen, or the giant spermatozooids which are produced within the ovules – these, so far as they are concerned, are just instrumental in getting the female plants fertilized, so that they may bear their great, glossy, plum-sized seeds. These they will gather, and slice, and wash, and wash again, and finally dry and grind to form the finest fadang flour. Like connoisseurs, choosing only the best, Tommy and his mother went from tree to tree – this one was unfertilized, that one unripe, but there was a carpophyll of heavy ripe seeds, a cluster of a dozen or more. Tommy sliced the machete, and caught the cluster as it fell. He poked another cluster, too high to chop, with a stick he was carrying, and asked me to catch the seeds as they fell. I found my fingers covered with sticky white sap. ‘That’s really poisonous,’ said Tommy. ‘Don’t lick your fingers.’

It was not just the reproductive structures of cycads which so fascinated me as a boy, or the sheer gigantism that seemed characteristic of the group (the biggest spermatozooids, the biggest egg cells, the biggest growing apices, the biggest cones, the biggest everything in the vegetable world) – though (I could not deny it) these had a certain appeal. It was rather the sense that cycads were brilliantly adaptable and resourceful life-forms, full of unusual capacities and developments which had enabled them to survive for a quarter of a billion years, when so many of their contemporaries had fallen by the way. (Maybe they had been so poisonous to fend off the dinosaurs which ate them, I used to speculate as a child – maybe they had been responsible for the dinosaurs’ extinction!)

It was true that cycads had the largest growing apices of any vascular plant, but, equally to the point, these delicate apices were beautifully protected by persistent leaf bases, enabling the plants to be fire resistant, everything resistant, to an unusual degree, and to reshoot new fronds, after a catastrophe, sooner than anything else. And if something did nonetheless befall the growing apices, the plants had an alternative, bulbils, which they could fall back on. Cycads could be pollinated by wind – or insects, they were not choosy: they had avoided the path of overspecialization which had done in so many species over the last half-billion years.[89] In the absence of fertilization, they could propagate asexually, by offsets and suckers (there was a suggestion too that some plants were able to spontaneously change sex). Many cycad species had developed unique ‘cor-raloid’ roots, where they symbiosed with blue-green algae, which could fix atmospheric nitrogen for them, rather than relying solely on organic nitrogen from the soil. This struck me as particularly brilliant – and highly adaptive should the seeds fall on impoverished soils; it had taken legumes, flowering plants, another hundred million years to achieve a similar trick.[90]