In Praise of Chametz – Part 1: The Botanical Origins

Rachel Safman:

It is really a joy this evening to be welcoming my partner-in-crime Jerry Davis as our honored guest in our Scientists in Synagogues series.

For those who may not be aware, Jerry is the one who took the bait, so to speak, when I first floated the idea of running this series in our congregation, of being among those seeking the support of Clal, an organization I admire deeply that works to constantly be revitalizing Jewish life in our country, for bringing contemporary ideas from the sciences into a Jewish context. And when I put the idea before Jerry, who I didn’t know terribly well at the time, he said, “Well, that sounds just dandy, sketch out for me what you’re thinking, and I’ll go sketch back what I’m thinking in return.” And so, a collaboration was born. 

And the program this evening, I think, in so many ways, embodies what’s so magical about this sort of dialogue between the secular sciences and Jewish thought, because I think for both of us – now I’ll speak for myself personally  – the process of preparing for this evening’s talk, and of talking things through with Jerry in advance, gave me so much more of an appreciation for what Jewish sources and Jewish voices brought to the discussion, much less, all the information that we’re going to be getting from Jerry over the course of this evening.

Jerry, of course, has spent – as far as I know – his entire professional career looking at members of the grass family through a diversity of lenses, a diversity of disciplinary lenses, and diversity of tools, in order to better understand how this family of plants has come to assume their present form biologically, but by extension, how they have come to be so central in our lives as settled people. And it is on both of those topics, woven together with a really compelling narrative, that he is going to lead off this evening’s discussion, taking us on a quick-and-dirty – if that’s the correct description – tour of some of the main principles of the work that he has been pursuing over the course of decades. We’re going to get just, of course, the most superficial understanding what it is that has occupied him, and that continues to occupy him, and even though he’s American, but with that, I think will come to have a deeper understanding of our own tradition, and how the grains come to figure to see your folks here.

Jerrold Davis: Thank you very much, Rabbi. It’s nice to see you folks here. I think I know almost everybody who I see on my screen, and I hope I’ve pitched this properly. You can get pretty nerdy when you start talking about what you do every day, and the people you’re used to talking with kind of speak the same language. But at the same time, I think there’s a certain amount of beauty in these sorts of things. So, I hope you’ll bear with me, and I hope you find something of value in this. 

So this is a wheat plant at the right, and a general outline of my discussion this evening appears at the left.

First of all, I’m going to talk a little bit about botany, about plant biology, and in particular, some of the peculiar characteristics of grasses. Secondly, I’ll just touch on the idea of what role grasses might have played in the origin of our species. And then thirdly, I’ll talk about some aspects of plant domestication, and try to bring it around towards the end (where I’ll perform a handoff to Rabbi Safman) to the ideas of chametz, and kitniyot, and the role of grasses, really, in our cultural history.

So there is, of course, the characteristic list that we’ve seen of the seven species that are going to be in the land that the Jewish people are given. A land with wheat and barley, vines, figs, pomegranates, olive trees and honey. And I have to say, it was like working on a term paper to begin to pull this together. And I always thought honey was honey – as in bee honey. But this was the point where I began to stumble across the idea that no, actually, it was a sweetened confection made from dates, an extract of the date sugar. And so far I haven’t seen or heard any contradictions. But as you’ll see in a few moments, I’m going to try to be very careful about signaling what I feel pretty sure of, what I’ve heard from a few reliable sources, and what I’ve stumbled across that might or might not have any basis in reality. 

And this is where I touch upon the idea that I mentioned just a little while ago, before we began this program, which is that I discovered what, for me, was the strange parallel between my own studies and the study of science and evolutionary biology, and in particular, what I would call religious studies. And I’ll get around to what I mean by that in a moment. 

So two of these items, two of the key items that are going to be found in the land of milk and honey, are wheat and barley. And I have spent most of my career – I won’t tell the stories about my misunderstandings with my professor from Kansas, Beth knows what story I’m referring to, but I became interested in the grass family early on. And as a student of plant diversity, I found it a fascinating area, and one that a lot of people were afraid to wander into, but it’s taken me to some great places in my career. And I’ve gotten to know some strange people who have similar interests and it’s – you might say, grass family. So, what’s that? Actually, after one talk, I had a student a number of years ago come up and say, “I thought grasses were like, you know, there’s one species of grass – grass. The grass you walk on on your lawn.” There are actually about 12,000 species in the grass family. It’s one of the largest families of flowering plants. And it includes quite a variety of plants that grow in very moist, very dry, Arctic, Alpine, tropical habitats. It’s truly a family that’s spread out all over the world. And it does include the bamboos, which are these giant grasses, but they fit right in with the rest of the family, and they’re actually not that far from rice. No jokes, please, about hybrids, we could make, but the bamboos and the rice group are kind of neighbors. 

And that would be basically one of the largest of the bamboos. They’re not all quite that size. 

So a couple of weeks ago, on one of my mail programs online, I noticed a little bit of clickbait. And it said, “Why zebras have stripes: somebody’s finally figured it out.” And I thought, you know, “I’ve seen somebody ‘finally figure it out’ pretty much all my life.” And this is the parallel that I wanted to draw between evolutionary biology in particular, but certainly, we could say it about other branches of science, and religious studies, which are that there are all kinds of definitive statements where people tell you “Now, we know X.” I was actually studying up for Pesach, and I was looking things up like “Why do we dip twice?” And, you know, there are a lot of statements about why we dip twice, and they’re mutually exclusive in many cases, and the people who give those reasons seem to be absolutely sure that their explanation is the right one. So again, I hope I signal properly, as I come to these points, where “here’s something that we’re pretty sure of it” and “here’s something that maybe not so much.

So here comes the botany part of the talk. This is a sugarcane plant, and one pretty basic thing about a grass is that they have leaves that are divided into two parts, and there’s the sheath part that’s down below, that wraps around the stem, and then there’s a junction where the blade actually branches off, and it’s the blade that we notice when we look at grasses growing on the lawn or wherever. There’s a lot of variety within the family – this is the kind of book, like only ten people in North America would ever be interested in looking at. But there are all these differences among various groups within this large family. What I want to point out is that if you’ve gardened, if you pruned trees and shrubs, if you’ve watched the deer, destroy the plants in your yard, you’re probably very weird that topping off or pinching off a plant tends to basically keep it from growing. It may branch again from down below, but plants grow from the tips, and when you cut off the tip, you pretty much stop that stem and that plant from elongating in that place. Grasses have a very interesting invention that just isn’t found in any other plants, and that is the ability to continue to produce the leaves – the leaf blade – by growing from a point below the tip I indicated.

There’s the leaf sheaf and then the blade, and there’s this region of growth. And long before there were lawn mowers, there were grasslands with grazers. And grazers come, and they snip off the top, and then move on. And the grass regenerates, not by branching, not by putting up new stems, but by simply continuing to regenerate the same leaf that was taken off up above. This is a very, very important part of grassland ecology – grazers, that sort of thing. And it’s one of the reasons – you see here we’re getting into “why?”, and that’s where things always get chancey – so I’ll say it’s one of the reasons that are generally cited for why grasses are so successful, and how they basically produced grassland, savannas, and any number of other different types of habitats in which they are the predominant plants. 

So that’s item #1 about about grasses, and I only have two more, so bear with me. And we’ll come around to the importance of some of these things in terms of the general direction of the talk. The second is, yes, indeed, they are flowering plants. They have what every flowering plant has, which is a stamen, which you see in this tulip flower around the periphery inside the petals, but outside of the pistil. The pistil is the central part. And as you probably all know, in insect or bird-pollinated plants, the pollen is taken from plant to plant, and that helps to affect cross-fertilization. So we see the pollen being produced in the stamens, and if it is placed in the proper location, on the pistil of another flower of the same species, we will get a fruit, because that pistil in the middle is the structure that ripens to form a fruit. So we could just call them fruiting plants instead of flowering plants. The two go hand-in-hand.

Well, grasses really, truly are flowering plants. And here we see several small flowers with some associated other structures, but you can clearly see the stamens. And you can see the feathery apices of the pistil. And being wind-pollinated, the stamens pop open, the pollen blows in the wind in this case, and so they’re not showy; there’s nothing to attract in terms of animal visitors. The pollen lands on these feathery stigmas, which have a very large surface area, and cross-fertilization is effected.

Some flowering plants produce fruits that have many, many seeds inside. And here’s a beautiful painting of a pomegranate I stumbled across many years ago. It would be difficult for me to trace back where I found it, but that is a fruit with many seeds inside. Other flowering plants produce one-seeded fruits, and so there is one seed inside of a peach or an apricot or a plum. And it is indeed, just as we saw on the pomegranate, a fruit, but in this case with a single seed inside.

And so grasses, being flowering plants, are going to have a pistil that ripens into a fruit. And this is the fruit, not the seed, of a grass plant. And it should be familiar if you’ve looked at grains of corn, grains of wheat, grains of rice. And it’s my breeding that makes me want to emphasize – it’s not a seed, it’s a fruit. And you can see that the outermost layer is indeed the fruit wall. 

So what else does the fruit have? Everything but that outermost layer is the seed inside this one seeded fruit. And what you can see is a pretty nice package of goods. The seed coat and the fruit wall are what give us roughage in our diet. If we eat whole grains, that’s the bran. The embryo is the wheat germ, or corn germ – that is, the the structure that’s going to develop into another adult plant.

The endosperm is the largest portion of what we see. This is predominantly starch, and it also includes inclusions of protein, and there are oils in the plant and various other sorts of things. If you have problems with gluten, then let me point out – and I’ll come back to this – that gluten is a type of protein, a storage protein is found in wheat. And it’s found there in that endosperm area. And it’s basically present to help the developing plant of the next generation, which needs its protein before it can begin to manufacture its own. So oil, protein, starch, roughage, it’s really quite a good food. 

And here we simply see a stack of wheat fruits. I’m not going to keep insisting on it now that we all know, but basically, these are the fruits/seeds of a wheat plant. And if you look closely, you can see the little wheat germ at the base of each one of them.

Okay, that was two items. I mentioned the leaves that grow from the base, I mentioned the fact that they’re flowering plants that have flowers and fruits, and here’s number three. And that is that plants do something very, very, very frequently that animals – basically, every once in awhile, you find an example of it, but it’s not very common. And that is a situation called polyploidy, where two species that will hybridize and produce what we call an F1 hybrid, the first generation of hybridization.

And I’ve used these green and orange dots to show you the chromosomes that come from one species and those that come from another. And because they are pretty similar – these being closely related species – but not similar enough, this hybrid, though it may be a successful plant, is going to be sterile. It can’t reproduce because its chromosomes don’t match up very well. And what happens very frequently in plants – in fact, the majority of plant species are what we call polyploids – is that if you have this is hybrid, which is sterile, and the entire set of chromosomes doubles, what we see is the restoration of fertility, because now we have two green large chromosomes, and two orange, and everything is in pairs again. In fact, we have everything from species A and everything from species B, and they’re summed together in this resulting plant.

Now, give you a peek ahead. Polyploidy – polyploidization as a process was all worked out in the early 20th century, after chromosomes were first discovered. One of the prime examples was wheat, because it is one of the most prominent examples of this phenomenon. And so what you end up with is a new species that is in fact sterile if it crosses with either of its predecessors, and it’s successful and may have a future. 

So this is very, very common in plants, and in particular, grasses are one of those families in which this is very frequent. So as I indicated, they’re very successful plants that dominate many ecosystems. Here is a savannah, and you can see a savannah is a grassland that has woody plants scattered amongst the grasses. Basically, if it gets a little moister – if the conditions change – you get a forest. If it gets a little dryer, you get a grassland without the woody plants. And the savanna is this sort of a magical balance in between. Sometimes it’s maintained by a certain nutrient balance in the soils. Sometimes it’s fire that comes through and that helps to maintain this sort of unstable intermediate between a forest and a grassland. 

And grasses are very, very frequently cited as having been important in terms of the origin of our species. This is where – let’s go back and think about the zebra again. We see correlations of characteristics, we see various suggestions that X might have caused Y, so I’m not going to say, “I know what the truth is”, but I’ll tell you what many, many people have had pointed out through the years as the fossil record of humans has developed, and as we’ve looked at the environments in which our ancestors lived. 

So I wrote down a couple of facts here. The genus homo, which includes many species, all of them extinct except our own, seemed to first appear about 2.3 million years ago, and we seem to still be around. Two of the key characteristics, two of the attributes by which we differ from some of our closest relatives, is that we are indeed bipedal, and some of us are intelligent. Many of us are. And if you recall, Cary Grant does escape from that airplane, so, give him some credit. It took brains and it took bipedalism to get him through. Our particular species, Homo sapiens – and of course, is very, very difficult to draw these lines – but people point to a date about two million years after homo, the genus, had appeared, and say, “We can call it homo sapiens around 300,000 years ago.”

Well, what do we have before the genus homo appears? Basically, although people fight about the taxonomy, people have generally come to focus on a genus called Australopithecus. Australopithecus, the southern ape. And again, there are many species of this particular genus, and some lived side-by-side and some followed the others through the years. And they first appeared about 4.2 million years ago and lived until about 2 million years ago. They were bipedal, as we are. And it doesn’t take too much hip anatomy and foot anatomy to be able to demonstrate that they were principally bipedal, rather than principally, say, knuckle-walking, as most of our closest living relatives are. 

So they existed side-by-side with our genus homo for about 300,000 years, 2.3 to 2 million years ago. And the point here – and it was argued about until the fossil record of humans and our relatives was built up – it used to be argued that once we were intelligent, we became bipedal, but it’s pretty certain that it happened the other way around. What we had are organisms that are as bipedal as we are – (and this isn’t the most obvious case; there are others) – they were walking around on two legs, but they were still apes in terms of from the neck up. They had small brains and there are various other anatomical features that say they’re really not us. 

So here’s where the grasses come in. It has been argued by many people – I can’t prove it’s so, so I won’t even assert that I think it’s so – but it comes up time and time again, as people speculate how this might have happened, that basically all of our relatives were forest dwellers – orangutans, gorillas, chimpanzees, to this day, are forest dwellers, and that bipedalism was an adaptation to more open grass and savanna environments. You could see the other organisms that were out there. You could carry things. And the argument goes – and of course, it’s very hard to say, “this must be so” – but the argument goes that bipedalism got people out of the forest and into the savanna, and that once we were walking around, carrying things, communicating with each other, the other attributes of humanity kind of proved to be pretty adaptive as well, and that the increase in brain size and ability to speak, all of those were, were fundamentally adaptations to the grasslands environment. Okay, take it or leave it, nobody knows for sure. And I’ve seen some alternative arguments.

 Let’s jump forward a little bit of a ways and and we now come to the beginning of agriculture. And there are three or four periods I’ll come to in a moment – stages in the development of agriculture. But what I want you to see is there’s this curious aspect, that sometime around 10,800 years ago, precisely in the area of modern Israel, Syria, Jordan, the so-called Fertile Crescent, but apparently earlier, over on the western side, seven or eight – I should say eight species are in cultivation. Three of them are grasses – two kinds of wheat, einkorn and emmer wheat, along with barley, and four legume species, lentils, peas, chickpeas and bitter vetch, plus one more, flax, typically used for fiber – but also, if you’ve eaten flax seed, it’s a plant that people consume. So it’s mostly grasses and it’s mostly legumes. And the little stars that you see in each of these archaeological sites indicate which ones of those eight are present. And they kind of pop up all at the same time at most of those sites. You don’t see eight radiating arms from every one of those sites, but you see six or seven in most of those cases. And there they are. 

But I want to point out an important part of this earliest evidence of plant domestication, okay. And that’s a loaded phrase that has to be unpacked a little bit. Let me go back and remind you about polyploidy, and talk about what some of these wheats are. Some of these terms are very common. They’re used all the time. You’ll find certain kinds of wheat – not so frequently in some stores, but maybe if you go to a natural food store, you will find others. And I want to give you a little of a sense of what they are. But first, I talked about hybridization, chromosome doubling, and the origin of a new species. And what I’d like you to see here is that there are two species that have just two sets of chromosomes up in the top row, urartu and speltoides. And they hybridize – went through polyploidization process – and produced something called triticum tergidum, which is in the middle. And as you can see, it has all the genes, all the chromosomes, of the other two. One is AA, one is BB, and they’re the AABB tetraploid. 

Sometime later, a third species over on the right, Triticum tauschii, which is labeled as DD to designate its chromosomes, hybridized with turgidum and produced what’s called a hexaploid – it had six sets of chromosomes. So down at the bottom you see triticum spelta. If you’ve heard of spelt wheat, yes, that’s where we’re going. And it’s an AABBDD hexaploid. And from that, over on the bottom left, developed the modern bread wheats, triticum aestivum. And this is many, many years of many people making crosses, looking at genes, looking at chromosomes, that have gotten us to the point where all of this could have been worked out. There were some mysteries about it until not too long ago. They got diploids, tetraploids and hexaploids that are all called wheat.

And here are some of the groups that fall into each of these categories. The einkorn wheat is basically not grown very commonly. If you look for it now, you can still find it. These are the original diploid wheats. And in the archaeological record, we find both wild and domesticated forms of this particular diploid wheat. The tetraploid wheats, generally known as a group as the emmer wheats, include the wheats that tend to be used for macaroni and noodles and various other sorts of things. So durum wheat, kamut wheat, these tetraploids also occur in wild and domesticated forms. 

And then there are the hexaploid wheats, the set that have six sets of chromosomes. And there is no known wild species that has that chromosomal makeup. They exist only in cultivation, and I’ll explain a little bit about that in a moment. So they are not among those early domesticates that I was just showing. But if you’ve ever enjoyed spelt wheat, that is a very ancient form, one of the original forms of that hexaploid bread wheat. And then there’s the modern triticum aestivum, the hexaploid weed that 95% of the time, when people say “wheat,” that’s the one they’re talking about. They’re known as the bread wheats. They have a lot of gluten in them. I mentioned gluten already, and it’s the gluten that is in the grains that helps them to produce a raised bread, because they hold together during the fermentation process. Just at the bottom, I’ve noted, that’s one of a few other kind of footnotes, other forms of wheat that have arisen independently in different places repeatedly. It’s a bit of a complicated mess. But these three sets are the ones that certainly constitute most of the things that are grown in agriculture and are called wheats. 

So if we talked about – now, I mentioned that early phase, where we saw the first phase of domestication. I’m not going to read through this whole slide, but what I want to point out is that sometime around 13,000 years ago, people began to collect wheat. They began, as you can see in the second line, [to collect] barley, oats, rye, seeds of other sorts of plants, fruits, roots. Hunter-gatherers gathering wild plants, including wheat, and barley, oats, the things that we saw in cultivation in an earlier slide. And the technology associated with that – sickles, pestles, pounding stones, querns for grinding the wheat, storage pits. 

So people were collecting in the wild, they were storing, they were basically making food products from these wheats. And it was just, as you can see, the einkorn are the diploid and the tetraploid wheats that were being collected, in terms of the wheat itself. 

In the next phase, people began to domesticate, and the opening phase of that is cultivation of the wild forms. If we look at the remains, they are no different from those that were being collected. But now they’re being planted out. And people are discovering that if they plant the seeds and protect the garden, they’ll be able to collect again in greater abundance. And sometime after that, as people begin to prefer certain grains, and to select those characteristics that are most useful for cultivation, what we see – and this is the phase I referred to earlier as the cultivation, not of wild forms, but of domesticated forms. And this is where sheep and goats are being domesticated. And then by about 6,000-7,000 years ago, wheat culture – that is, all of these plants and all of this technology – are beginning to spread away from this land where they were initially brought in, to places like Central Asia, southern Europe and Egypt. 

So, by about 6,000- 7,000 years ago, the Egyptians were growing wheat. Here’s where we get to the bread-wheat story. It was sometime during this period that we first see the hexaploid wheat. It is not a species that was selected from the wild plants that were growing in the region; it was a hybrid that appeared in somebody’s wheat field. And it was more robust, and it produced a wheat that was better for making bread, and people selected it and began to propagate it. So it is a species that never existed outside of human agriculture. 

And then I want to show you on the bottom that there’s the question: how do we know that the plants have been domesticated? How do we know that people have selected new forms? And what you see changing at the archaeological sites are an increase in the number and the size of the grain in an individual sheaf of wheat, a shift to what we call a non-shattering form. If you can grab the head off of a wheat plant and bring it back, without it breaking into a thousand pieces and dropping the seed on the ground, that’s a preferred agricultural attribute – and then one that free-threshes – that is to say that the little brans, the little papery structures that surround the grains, fall free from the grains themselves. 

So it is by this sort of evidence that we can begin to argue that the plants are changing under our care and under our selection. Here’s something that actually showed up in a beautiful figure in the New York Times a number of years ago. And it just charts the spread of certain artifacts of wheat culture over on the right, out of Turkey and into southern Europe, and that it represents a phase of European civilization that basically derived from wheat culture, according to certain technologies and certain art forms, spreading from the ancient Middle East. 

So I just want to show you again, the emmer wheat on the top left and the wild and the domesticated. The domesticated sheaf holds together. The grains are beginning to be free from the the little papery brans that surround them, so you see naked grains showing up that are more easily broken out. And so basically, the whole inflorescence holding together and the grains being easily removed are two very key characteristics. When we begin to see these features, we can begin to argue that humans are actually changing the plants by selecting those particular attributes. And I’m just showing you – this I showed a moment ago. It’s just to indicate it is those two features down on the bottom, plus the increase in the number and in the overall sheaf, the number of grains and the size of the grains in each inflorescence. 

So, I want to say a word or two about gluten, and I want to make it very clear that this is something [where] everything I know about it is “something I’ve read here and there.” There are a lot of “everything you need to know about gluten” websites, and I decided to pick one that I could trust more than others, the Mayo Clinic. But do not take anything that I say as advice. This is something – I’m just a beginner in learning about, and I’m sure there are people in the congregation who have dealt with this. I know of a few. And I just want to point out how how gluten, first of all, gluten sensitivity comes in the number of forms in a number of degrees, okay. It’s mostly wheat, barely, rye, triticale, which is a later hybrid between wheat and rye. Maybe oats — you can see that about the middle of the page. Oats are not as closely related, and some people have a problem with it and others, not so much. 

But you’ll notice just above that about the middle of the page that when we say wheat, we’re talking about durum, einkorn, kamut, spelt, all of them have gluten in them. And here we might be getting into the realm of what’s chametz and what’s kitniyot, because there are all those other grasses. 

And so, the sorts of things that can be used to make bread, but do not belong to the gluten-containing grasses, are found in the bottom section. And I’ve highlighted, the ones that actually are grasses. So corn, rice in their various forms, the millets, the grasses – teff, if you’ve had them, they’re in the same family, but there is some distance from the wheat group, in terms of the diversity of the whole family. And they do not have gluten. But just because I read that somewhere doesn’t mean that you should trust me that you can eat these safely. Don’t take your advice from me. Okay? I think I’ve said that enough times. But that’s the gluten connection, in general, to these original cultivated plants. 

Here’s something that jumped out at me when I went looking for references. The seventh plague is by barad – “Moses held out his hand, held out his Rod toward the sky, Adonai sent Thunder and hail, the fire streamed down to the ground, and Adonai rained down hail upon the land of Egypt. The flax and barley were ruined, for the barley was in the ear, in the flax was in the bud. The wheat and the emmer (another kind of wheat) were not hurt, for they ripen late.” (Exodus 9:23-35)

Wheat does ripen later than barley. Barley begins to be ripe just around Passover. And about 49 or 50 days later, just about the time of Shavuot, we see the time of the first fruits of wheat. So barley is literally being harvested from Passover on through to about Shavuot. And these are generalizations – there many climatic differences, there are main strains and varieties of these plants. But there is a very clear (keeping the zebra in mind) in many texts of Passover and Shavuot to the barley and later the wheat harvest, and that using sheafs of barley, we can actually count the days that take us from Passover to Shavuot.

And this brings us – I’m just about done here, but this brings us to the calendar, in which Nisan, the month in which Passover occurs, is generally in March-April. And if we start at the beginning of a year that happens to fall where Nisan begins on April 1st, we count the 12 months of the year, and counterclockwise from the center here, we reach Adar and it’s time for Nisan again. But it’s a little too early, because it’s not a full 365 days to go through those twelve months. And so the years creep up on us. But the Torah says that holidays take place at certain times of the year, and the rabbis have adjusted. So in the second year, Nisan begins a little too early. In the third year, it begins again even earlier. And once you reach a certain point – and it’s been worked out mathematically, now, how to do it – but a few thousand years ago, it hadn’t been mathematically worked out, and so we had a second Adar. And the second Adar helps Nisan to be at the right time of the year so the barley harvest, and later, the wheat harvest, will occur in the proper months. And that, according to my understanding, is the origin and the purpose of extending the year in this manner.

And again, I’m on very thin ice here, and I’m about to do the handoff – that in fact, before the mathematics had been worked out, this was a case that was brought to the Sanhedrin every year, and they would decide if it was one of those years in which a second Adar was needed in order to give time for the barley harvest to take place in Nissan. 

So I want to thank you for listening to this kind of rambling talk about how the biology of grasses relates to our history and our culture, and I hope you found something of use in it.