'Twas the Eve of the Cretaceous


Leo J. Hickey

‘Twas the eve of the Cretaceous, when all through the forest
Not a creature was stirring, not even the poorest;
The branches were hung with festoonery mosses,
Dripping and streaming like rain-sodden flosses.
None were the ovules nestled snug in their carpels,
Awaiting stigmatic fertilization’s marvels.
In all of this dense-packed, luxuriant bowery,
The eye searched in vain for fruiting or flowery.
High and wide did great conifer trunks tower,
Casting on rivals their gloom and their glower;
While members of many more lowly plant clades,
Sought out the sunshine on banks and in glades.
No buzz or hum of nectar-laden bee,
Nor the sweet delights of frugivory;
Only the sounds of horrendous munching,
As saurian hoards commenced their lunching.
Whilst time wound its slow course toward the Albian Age,
Evolution recast the company on Nature’s vast stage,
And what our wondering eyes should appear,
But a flowery little seed plant, just beginning its career.
It started to germinate so lively and quick,
It’s clear to us this was Evolution’s new trick.
More rapidly than continents drift its innovations came,
Giving anthophytes the upper hand in Selection’s mighty game.
This plant was herbaceous or not more than a shrubbery,
With stem and branches looking decidedly most rubbery,
Its flowers diminutive in spikes or in thryses,
Too small and too drab to inspire any verses.
Yet with double fertilization and ovular reduction,
And increasingly more winsome ways of insectivorous seduction;
Their rapid growth and weediness gave them a special ability,
To grow and prosper on riverine plains of frightful instability.
And so at an ever increasing pace,
The angiosperms commenced their race,
Displacing the fernery on tangled bank,
With fast-growing leaves of first and second rank.
Next they assaulted the dark sylvan fastness,
Finding burned swathes in the midst of its vastness;
And as the myriad of ages passed by,
They reached their trunks unto the sky.
Of the great night that ended the dinosaurian reign,
Flowering plants weathered the blast with scant strain;
And charged one tiny mammalian line with sowing,
All the many fruits and nuts that soon started growing.
The result was to give our ancestors color vision,
Adding considerably to their fruit-selective precision;
And thus preventing multiple and painful bellyaches,
Or even more threatening gustatorial mistakes.
Now with these adaptations anchored firmly in place,
The angiosperms pulled to the head of the race;
And so throughout the landscape from the equator to the pole,
Hardly a place is seen today that lacks its flowery dole.
The moral of this tale comes out clearly and neatly:
The path to success is growing quickly and cheaply.
And now I exclaim with a shout and a cheer:
Happy Christmas to All, and to All a Good Year!

Leo J. Hickey - 2011

A watercolour painting meant to look like a fossil plant. The background is a sandy light brown with water droplets that add texture. In the centre at a 45 degree angle is a long, skinny, dark brown plant. It resembles Hornwort, having one long, sturdy stem and a lot of little branching leaves, each a very short stem with about 4-6 leaves coming off them. The painting is signed ML
Guest art by Megan Leslie

This poem was submitted to us by Dan Brinkman at the Yale Peabody Museum of Paleontology (YPMP). Leo J. Hickey and his wife Judy sent the poem out as a Christmas letter to his colleagues in 2011. The art here by Megan Leslie is based both on the poem and on Leo’s early research involving cleared and stained extant leaves.

The natural history of this poem

In his poem, Leo Hickey focusses on the evolution of flowering plants (Angiosperms) from the Jurassic through to the Paleocene. Leo explains how during the Jurassic and early Cretaceous there were only plants such as mosses, ferns, and conifers; that there were no “ovules nestled snug in their carpels (referring to angiosperm reproductive organs)” and “eyes searched in vain for fruiting or flowery” (not an angiosperm to be seen anywhere!). Everything changed in the Albian stage of the Cretaceous (113-100.5 Ma), when angiosperms quickly became much more diverse, and went on to change Earth’s landscape “from equator to pole”.

Leo points out several adaptations that allowed angiosperms to spread so widely and so quickly. This first is “double fertilization and ovular reduction,” which are the processes through which flowering plants produce pollen to fertilize other plants with. This pollen contains two sperm, and when it comes in contact another plant it will begin the process of seed production. Next is “insectivorous seduction,” which simply refers to how flowering plants evolved to often lure and rely on insects and other animals to help spread their small and easily carried pollen from plan to plant. Third, Leo mentions that angiosperms have “rapid growth and weediness” which allowed them to outgrow plants they compete with and grow in environments that other plants could not.

Finally, Leo talks about how the evolution of fruit colour and primates is intertwined. A prominent theory of primate evolution suggest that primate colour vision evolved to better spot differently coloured fruits, which early primates ate. This would allow primates to find fruits that would not poison them and provide the best nutrition. Many fruiting plants evolved to produce more and differently coloured fruit to attract primates to eat them (to help spread their seeds) or to stay away (not all plants have nutritional value), making seeing different colour increasingly important for early primates.

Leo J. Hickey

Despite the apparent message in the last stanza of his poem, Leo Hickey had a long and fruitful career in palaeobotany. Leo spent his life in the lab and in the field, untangling long-accepted but faulty methods of determining plant phylogeny. Early in his career, Leo worked out a method of categorizing fossil leaves based on the architecture of their veins and how they compared to modern plants.

Much of his research at the Yale Peabody Museum was related to that of Glenn Jepsen. They both looked at Paleocene Wyoming to study life after the extinction of the dinosaurs. Leo integrated sedimentology into his palaeobotanical research to reconstruct ancient environments. He accompanied Mary Dawson to Ellesmere Island in Nunavut Territory, where he collected unique data on the sub-tropical plants that grew there during the Paleocene-Eocene Thermal Maximum, one of the hottest periods of life on Earth after the dinosaurs went extinct.

Leo Hickey

Leo worked nonstop to lay out new groundwork for the study of fossil plants, but even in the field he kept up “certain formalities.” Every day, Leo wore a brimmed field hat and a clean khaki shirt, and was known to enjoy “chocolate chip cookies at lunch, and a bourbon in the evening.”