Twins!

Alternative title: Two for the Price of One!
by Jörg Witticke, Beyernaumburg, Germany
Chamaerops No.34 Spring 1999

A few years ago I attended the summer meeting of the EPS in the city of Rome. Daring the trip I collected from the Rome Botanic Gardens some seeds of Butia capitata and Butia eriospatha These seeds were duly taken home for germination. But what a surprise T got when I found that some seeds had developed not just one primary root, hut two or three! I wanted to know more about this phenomenon so I consulted my palm books. None, however had any mention of such occurrences. I am therefore forced to write my own experiences on this matter.

TWINS I call it. That is, two plants developing from one seed. Although rare in the plant kingdom it does appear to occur again and again. It occurs in palms with a frequency which varies from species to species. According to observations there are two fundamental conditions for TWINS development in palm trees. Each palm seed has either one or three germ pores, as I would like to call them, which can be recognised as the point at which the initial root is forced out. The clearest example of these germ pores is in the coconut palm Cocos nucifera These seeds have three such pores and can be easily seen grouped together at one end of the seed. Other palm seeds also display these pores. The date palm has only one pore at the broadside opposite the logtitudinal groove.

However three germ pores alone do not in themselves guarantee development of more than one primary root. Behind each pore a separate germ chamber can be found. (This can be easily seen by cutting across a Butia capitata seed). The coconut in fact has only one germ chamber, thus it fails in respect of TWIN development. Palm species as a rule have only one germ pore. There are however exceptions. On occasion, palms develop a double seed, that is, two seeds are grown inside one single fruit. This often occurs in the species Caryota urens, one frequently gets two seeds and now and again both seeds will grow together. I have already had such seeds although up to now only one of the double seeds has germinated. I have been informed that a Sabal species has had both seeds of a double seed germinate.

What it is that triggers the development of TWINS from seeds with more than one germ pore I do not know. I proceed on the assumption that a hereditary ability exists. This supports my observations as I have observed the development of two primary roots from seeds of only certain mother trees. The development of TWINS occurs more often than one might expect. I have personally observed it several times. I have friends who have also observed it. The first time I discovered this peculiarity was in the seed of the species Maximiliana that I had received as Maximiliana regia To date though I have been unable to find mention of this species in any palm literature. My experience with Maximiliana was the last time I witnessed the frequent development of two germ roots.

I shall now mention the Butia capitata and B. eriospatha seeds I collected from the Rome botanic gardens and also some seeds of Butia paraguayensis which I collected whilst at the 1997 summer meeting in Almunecar, these have also germinated as TWINS. After germination I let the germ roots develop a short while prior to planting in to individual pots. I was then able to observe the development of two germ roots in the Butia seeds very well. Some of these Butia seeds even developed triplets. The individual germ roots break out on a successive basis with up to 15 days separating the initial sighting of individual germ roots. Only rarely have I observed two, not to mention three, roots developing simultaneously. It appears this delay in the development of the second primary root can be quite long. I have observed a seedling, which has suddenly put up a second initial germ leaf, giving the appearance that two seeds must have been in the one pot. I cannot however, comment on the future development of such TWINS. Of my Maximiliana seedlings one suffered the death of both germ roots at an early stage, the other developed as a normal single plant. A friend of mine has told me that it is normal for only one of the germ roots to develop a primary leaf.

Of my Butia twins/triplets I can say that the individual plants of one seed are well developed and there are no differences when compared with plants which have emerged as SINGLES from a seed. I believe this is due to the fact that each develops from an individual germ chamber, thus each plant has an equal amount of nutrients. My seedlings of Butia paraguayensis are still too small to comment on.