Editorial

Tobias W. Spanner, Tizianstr. 44, 80638 München, Germany

I am very pleased about the responses we got on our call for articles on palm seed germination, the results of which you can find in this issue. I think it is a particularly rewarding feeling to grow palms from seeds, especially when you can look back onto a whole garden full of self-grown palms one day, when they have matured. It is always amazing to see how a big tree can spring from such a tiny seed.

I often find that many perceive palm seed germination to be a problem, perhaps due to the fact that some palm seeds have a lengthy germination period. I would claim that a seed from a palm like Howea is not necessarily more difficult than that of a Livistona, for example, just because the Howea seed takes many months to sprout as opposed to a few days or so for the Livistona. One just needs to have more patience with palms like Howea and be aware of their germination period. Many palm seeds that are notably slow also often are notably reliable in their success and are hardy to adverse effects such as desiccation, the number one enemy of most palm seeds.

My recent personal germination discovery was with seeds of Trachycarpus. I had always wondered why Trachycarpus seeds that have been severely desiccated did not germinate well with standard methods, even though the seeds looked healthy and did not rot in any way. I have kept seeds of some Trachys in the seed beds for years, on occasion, without any signs of deterioration or, unfortunately, germination. Rehydration seems to be the secret to success! Testing out Trachy seeds that were badly desiccated, I found that they required up to two weeks of soaking before the embryo embedded in the seed was able to fully recover, swell and fill the small cavity in the endosperm.

A set of secateurs is a great tool to determine the hydration of a palm seed. By cutting the seed in half in the right spot, the embryo can be seen as a small, cone shaped lump of tissue embedded in the endosperm. In most palm seeds the embryo is located along the seed’s longitudinal axis, so cutting it lengthwise usually gives you a good result. In some seeds, like Butia, Syagrus or Sabal, it sits behind a germination pore that is easily visible on the endocarp or shell of the seed. Other palm seeds again hide their embryo well, such as Arenga and Caryota, and finding the embryo may require some searching. Be careful cutting hard shelled seeds this way so the secateurs’ blade won’t end up in your finger. Such seeds are better cracked with a hammer or a rock first before examining them.

The embryo in a palm seed is what will later develop into the plant; the rest of the seed is filled with a whitish material (endosperm) that gets digested to feed the embryo until it has grown into a seedling. The embryo usually has a white or yellowish colour and should fill the cavity it sits in to at least half. A brown or totally shrivelled embryo usually means the seed is no longer viable. Seeds where the embryo fills its cavity only partially would need to be well rehydrated; in contrast, seeds in which the embryo is fully swollen and filling its cavity are ready to sprout and need no soaking time. T.S.