Juniper

Local signs of spring: Some apricots blooming in village; prairie, hay fields, and purple asters greening; daffodils, mustard tansy, dandelions, and cheat grass up.

What’s happening in my yard: Roses, vinca, bouncing Bess, and chrysanthemums putting our new leaves; hyacinths growing; iris and grape hyacinths coming up.

What’s blooming inside: Bougainvillea, aptenia, rochea, and kalanchoë; snake plant put out new sprout.

Animal sightings: Horses brought in to pasture.

Weather: Storm sat over area for a week, early morning temperatures alternated between 20 and 40, rain finally fall Friday; 11:56 hours of daylight.

Weekly update: The first signs of spring have arrived - stuffy noses, runny eyes, sneezes.

Each year I listen to friends blame it on juniper blossoms. I fully sympathize with their miseries but I have a problem with the idea of an evergreen with flowers. Too many artists’ renderings of dinosaurs in swamps surrounded by giant ferns, mastodons feeding on grass, and graceful mammals cavorting with flowers and insects impressed on my young mind that conifers do not bloom.

They may have seed cones, but they don’t have petals. That was the great dividing line in plant development between the gymnosperms and the angiosperms. Indeed, it was the drying of the earth that led to the great revolution. The sperm of earlier plants moved through water. When water disappeared, natured adapted with pollen that sailed through the air.

The long extinct seed ferns that developed in the coal swamps of West Virginia in the upper Devonian were the first to use pollen. Imprints from characteristic leaves for the cypress family have been found in upper Triassic, and evidence of two existing junipers from the upper Cretaceous. The local sabina subgroup of junipers with serrated leaf edges appeared with the Madro-tertiary geoflora of the Eocene and early Oligocene in México.

Last weekend I walked out to the nearest juniper on the prairie to see what it is, in fact, they are doing this time of year that causes so much suffering.

The male tree had clusters of brown leaves mixed in with the green that looked like piñon nuts from a distance. The strobili had emerged last fall, and over the winter pollen had developed in sacs on their underbellies. When the cones on distant female trees reach puberty, their end scales will part and sticky droplets form. Soon after, these pollen sacs will open and fling their life force to the wind.

At the time it leaves the tree, the tiny, spherical pollen grain is shrouded in two layers. When it lands, the thick inner, intine layer absorbs moisture from the droplet and ruptures. That, in turn, expels proteins from cavities in the outer, exine layer. If the female recognizes the chemicals as gifts from an appropriate suitor, the drop will desicate and the pollen grain will be pulled into the female cone for fertilization.

When a misguided pollen grain lands in a moist human space, it still sends out protein scouts to determine if a pollen tube can follow. The first time, the body generates an allergen specific antibody that lodges on the surface of a mast cell. The next time a grain of pollen intrudes, a waiting immunoglobulin E antibody snatches it. When enough are captured, the underlying mast cells release histamines and other inflammatory substances that trigger allergic symptoms.

In Santa Fe, where temperatures are more moderate and water more plentiful than here in the valley, one-seeded junipers grow close enough along the road to form pygmy forests. Nature could perpetuate itself there with mild breezes. Here in the grasslands, hundreds of feet separate Juniperus monosperma trees. Everywhere pollens are released for weeks, and travel miles.

Outsiders arrive in northern New Mexico awed by what they see as an ancient land. In fact, the Oligocene mountains are so young they haven’t yet eroded enough to produce foothills. Instead, dumps of Santa Fe composites parallel the volcanic Jemez and uplifted Sangre de Cristo. The barren ridges and lower mountain sides have been colonized by a far older life form, the junipers. Each year unsuspecting latecomers find themselves trapped in nature’s primeval rite of spring when the very air they breathe is turned into a great fertility bath of floating pollen.

Notes:
Upper Devonian - 360-374 million years ago, Appalachians, seed ferns
Upper Triassic - 213-231 million years ago, desert, cypress family
Upper Cretaceous - 65-97.5 million years ago, swamps, junipers
Eocene - 38.0-54.9 million years ago - arid southwest, sabina clade of junipers
Oligocene - 24.6-38 million years ago - Sangre de Cristo uplift, first Jemez fault

Adams, Robert P. "The Serrate Leaf Margined Juniperus (Section Sabina) of the Western Hemisphere: Systematics and Evolution Based on Leaf Essential Oils and Random Amplified Polymorphic DNAs (RAPDs)," Biochemical Systematics and Ecology 28:975-989:2000.

Emberlin, Jean C. "Aerobiology" in William W. Busse and Stephen T. Holgate, Asthma and Rhinitis, volume 2, 2000 edition.

Mugnaini, Serena , Massimo Nepi, Massimo Guarnieri, Beti Piotto, and Ettore Pacini. "Pollination Drop in Juniperus communis: Response to Deposited Material," Annals of Botany 100:1475-81:2007, describes female behavior.

Stewart, Wilson N. and Gar W. Rothwell. Paleobotany and the Evolution of Plants, 1993 second edition.

Wodehouse, Roger P. Hayfever Plants, 1945, describes male behavior.

Photograph: Male one-seeded juniper with brown pollen cones between serrated green leaves, 7 March 2009.