Of Birds and Bayberries : Alfred j. Fordham Seed Dispersal and Propagation of Three Myrica Species

The genus Myrica comprises about 50 tral United States and from Europe to north- species (often ill-defined) distributed east Asia. throughout the temperate and subtropical All three of these species have nitrogen- areas of both hemispheres. The Arnold Ar- fixing root nodules, which enable them to boretum collection includes three species: thrive m areas where many other plants M. pensylvanica, M. cerifera, andM. gale. could not survive. They are dioecious - Myrica pensylvanica Lois., the common having staminate (male) and pistillate (fe- bayberry or candleberry, occurs naturally male) flowers on different plants - like hol- from Newfoundland to western New York lies and ashes. and Maryland, chiefly in poor soil. It is suck- The fruits of Myrica pensylvanica and M. ering in habit and tends to form shrubby cerifera are small (2.5-3 mm and 3.5~.5 mm clumps, which at maturity can range from 2 in diameter respectively) globose nuts with to 8 feet in height. Frequently it is found on waxlike coatings. It is this waxlike material roadside cuts, railroad banks, gravel pits, and that provides the fragrance in bayberry- other locations where topsoil has been re- scented candles and soap. It becomes bluish moved completely. In Boston its shiny green gray as it dries, making the thickly clustered leaves remain on the branches until No- fruits conspicuous in the landscape. The vember. They are fragrant when crushed, a fruits ripen in late September and are eaten characteristic of all Myrica species. by birds. Since birds lack teeth and cannot Myrica ceri fera L., the southern bayberry, chew, the hard-coated seeds pass undamaged wax myrtle, or southern wax myrtle, is an through their digestive systems. Only the evergreen plant native from east Texas and waxy coating is removed, and this is a pre- Oklahoma to Florida and as far north as New requisite for germination. The seeds then Jersey. Although the plants in the Ar- remain on the ground throughout the boretum are low in stature, the species can winter, satisfying another requirement for attain heights of 30 to 40 feet. germination, chilling, which activates the Myrica gale L., sweet gale, a deciduous embryo. shrub, occurs naturally in shallow waters The fruits of Myrica gale are different and swamps from Alaska to Newfoundland, from those of M. pensylvanica and M. ceri- Nova Scotia, and the northeastern and cen- fera. They are tightly packed around a cen- 21

tral axis to form short (8-10 mm) catkins Propagation by Seed that remain on the until In- plant spnng. To germinate the seeds of Myrica cerifera stead of the waxy coating of the other and M. pensylvanica artificially, one must species, two winglike bracts dotted with yel- create conditions resembling those of na- low resin enclose the fruit of M. gale. The ture : the waxy coating must be removed and bracts aid in the of the seeds fleshy dispersal the seeds placed in cold stratification at 40°F them afloat when by flotation, keeping they for three months. I divided fruits of M. ceri- fall into the water. Birds are not known to fera into four lots, each containing 100 eat the fruits of sweet gale. seeds, and treated them as outlined below (the fruits were collected on Bayberry plants (Myrica pensylvamca) growing in September 27, and the was done five months poor soil at the intersection of Routes I and 128 accounting in Dedham, Massachusetts. These plants un- later): doubtedly grew from seeds carried in the diges- Lot 1: Seeds were sown with wax remain- tive tracts of birds and dropped here. The trees m Six resulted. the background are red cedar (Jumperus vm- ing. seedlings gmana L.) and probably were spread by the Lot 2: Seeds with wax remaining were same means. placed in cold stratification at 40°F 22

Fruit and foliage of the common bayberry (Myrica pensylvamca~. lier in some years than in others. I once saw an immense stand of M. pensylvanica on for three months and then sown. Sev- Cape Cod heavily laden with fruits in Oc- enteen seedlings resulted. tober, but by mid-November all had been Lot 3: Seeds were sown with wax removed. eaten by birds. If the seeds are to be stored Six resulted. seedlings prior to treatment, the wax should not be Lot 4: Seeds with wax removed were placed removed, as it protects the seed from desicca- in cold stratification for three tion. months and then sown. General ger- The first step in germinating the seeds of mination resulted. Myrica pensylvanica andM. cerifera is to These results demonstrate the importance remove the waxy coating. Rubbing between of both wax removal and cold stratification the palms of the hands, rubbing on a wire to obtain complete germination with these screen, or soaking in warm water will ac- two species. Seed of Myrica gale requires complish this. Next, the dewaxed seeds only cold stratification - 3 months at 40°F must be combined with a medium such as - for general germination. damp sand or damp peat moss and the mix- Ripe fruits of Myrica can be collected eas- ture placed in a polyethylene plastic bag. ily by hand. At the Arnold Arboretum they The bag must be bound at the mouth with a are ready for collection in late summer. How rubber band to make it vapor proof. The long they remain on the plants varies from amount of the medium need only be two or year to year, for the birds remove them ear- three times the volume of the seeds, for at 23

sowing time the entire content of the bag BOOKS must be used, and excessive medium could lead to some seeds being embedded too deeply. The bag must then be placed in a 40°F for three after refrigerator months, The Pirion Pine: A Natural and Cultural which the contents are sown. When this History, by Ronald M. Lanner. With a Sec- procedure is followed, complete germination tion on Pine Nut Cookery by Harriette Lan- can be expected in about three weeks. ner. Reno, Nevada: University of Nevada Press. 208 pp. $13.50.

Vegetative Propagation RICHARD WARREN Myrica tends to be suckering in habit, and shoots with roots can be separated from From the Texas Panhandle almost to the around the bases of the New parent plants. Pacific Ocean, from Mexico to southern also can be started from softwood cut- plants Idaho, covering 70,000 square miles, grows tings. the pinon-juniper woodland, so little known to us in the East. In this compact volume References Professor Lanner tells us why this woodland Rehder, Alfred. 1940 Manual of Cultivated Trees and is important. He opens our eyes to its prehis- in America Second edition Shrubs Hardy North tory, its history, and its future. New York: Macmillan Pines to North Ehas, Thomas S 1971. "Genera of Myricaceae "Journal originally immigrated of the Arnold Arboretum, 52: 305-18. America from Asia. Some found temperate Schopmeyer, C S., comp 1974 Seeds of Woody Plants homes in our continent and in Europe. Oth- m the Umted States Agricultural Handbook ers went southward to Mexico and split into 450 Washington, D C : U.S. Department of Ag- nculture. many genetic variants, the forerunners of Ridley, H. N. 1930. The Dispersal of Plants Throughout the present bewildering array of Mexican the World. L Reeve: Ashford, England. pines. From them a group of drought-hardy, soft-wooded pines, with one to five leaves in a fascicle and large, wingless edible nuts, evolved to comprise the present 11 species of pinon pines recognized by the author. The uplift of the Sierra Nevada in the Pleiocene barred the moisture-laden Pacific winds from the interior of the continent they had formerly penetrated. This event brought a drought to the southwest of what was later to be the United States, and the redwoods there died, and the pinons, particularly Pinus monophylla, moved in. Lanner tells us of the birds, the animals, Alfred/. Fordham was formerly research horticulturist at the Arnold Arboretum Conunued on page 36