Serotiny and the Evolution of Seed Cone Size in Cupressaceae Conifers

2021 ◽  
Vol 182 (1) ◽  
pp. 9-18
Author(s):  
Karishma Swarup ◽  
Dori Contreras ◽  
Andrew B. Leslie
Keyword(s):  
Seed Cone

Mesocyparis borealis gen. et sp. nov.: fossil Cupressaceae from the early Tertiary of Saskatchewan, Canada

1987 ◽  
Vol 65 (11) ◽  
pp. 2338-2351 ◽  
Author(s):  
E. E. McIver ◽  
J. F. Basinger
Keyword(s):  
Northern Hemisphere ◽  
Branching Pattern ◽  
Natural Group ◽  
Classification Schemes ◽  
Cone Structure ◽  
Reproductive Morphology ◽  
Extant Genus ◽  
Early Tertiary ◽  
Seed Cone ◽  
First Time

Fossil cedar foliage of the Cupressinocladus interruptus type, with associated seeds and cones, is locally abundant in Paleocene deposits of the Ravenscrag Formation, southwestern Saskatchewan, Canada. Vegetative remains of this type occur frequently in early Tertiary plant assemblages throughout the northern hemisphere, indicating that this now extinct cedar was once widespread. For the first time this cedar can be described on the basis of both vegetative and reproductive morphology. Foliage is frond-like with a characteristic opposite branching pattern. Seed cones are globose and woody and bear four equal and decussate scales with prominent umbos. Seeds bear large, equal, semicircular wings. The fossil cedar appears most closely related to extant Cupressaceae such as Thuja, Chamaecyparis, and Heyderia. Foliage closely resembles that of Thuja, while cones are most similar to those of Chamaecyparis. The fossil differs sufficiently in foliage and seed cone structure to preclude assignment to an extant genus and is here assigned to Mesocyparis borealis gen. et sp. nov. Similarities among such extant genera as Thuja, Chamaecyparis, Heyderia, and Thujopsis and the fossil Mesocyparis borealis suggest that all may belong to a single natural group. Furthermore, this group may be more closely related to the southern hemispheric genera Libocedrus, Papuacedrus, and Austrocedrus than present classification schemes imply. Our examination of the Cupressaceae indicates that a revision of present systems of classification is required to accommodate evidence from both extant and extinct cedars.

scholarly journals A Taxodiaceous Seed Cone from the Triassic of Antarctica

1997 ◽  
Vol 84 (3) ◽  
pp. 343-354 ◽  
Author(s):  
Xuanli Yao ◽  
Thomas N. Taylor ◽  
Edith L. Taylor
Keyword(s):  
Seed Cone

Seed cone traits and insect damage in Tsuga canadensis (Pinaceae)

2004 ◽  
Vol 34 (1) ◽  
pp. 261-265 ◽  
Author(s):  
Jean J Turgeon ◽  
Chuck Jones ◽  
M Isabel Bellocq
Keyword(s):  
Seed Production ◽  
Tsuga Canadensis ◽  
Insect Damage ◽  
First Report ◽  
Seed Cone ◽  
Length Width ◽  
Maximum Proportion ◽  
Sterile Seed ◽  
The Impact ◽  
Filled Seeds

We measured seed cones of Tsuga canadensis (L.) Carrière, assessed seed potential (number of fertile scales × 2) and seed efficiency (number of filled seeds/seed potential), and estimated the impact of Eupithecia mutata Pearsall (Lepidoptera: Geometridae) and Megastigmus hoffmeyeri Walley (Hymenoptera: Torymidae) on seed production. Mean length, width, and volume of healthy cones varied little among sites from Ontario. Cones had about 28 scales; 13 were sterile. Seed potential and seed efficiency differed among sites, ranging from 25 to 31 ovules and 24% to 72%, respectively. The number of scales (both sterile and fertile) increased with cone volume, but the proportion of fertile scales was independent of cone size. The maximum proportion of cones infested by E. mutata was 21%. On average, each larva destroyed >90% of the filled seeds from each cone, thus from a practical perspective, the proportion of T. canadensis seeds destroyed per site was equivalent to the proportion of seed cones infested. The proportion of cones infested by M. hoffmeyeri ranged from 9% to 40%, but the proportion of seeds destroyed per site (range: 1.1%–6.1%) was much lower than that of E. mutata. The maximum number of M. hoffmeyeri-infested seeds per cone was seven. To our knowledge, this is the first report documenting cone traits of T. canadensis and the impact of E. mutata and M. hoffmeyeri.

Gibberellin A4/7 enhances seed-cone production in field-grown black spruce

1988 ◽  
Vol 18 (1) ◽  
pp. 139-142 ◽  
Author(s):  
Rong H. Ho
Keyword(s):  
Vitamin E ◽  
Black Spruce ◽  
Seed Orchard ◽  
Shoot Elongation ◽  
Bud Burst ◽  
Lateral Shoot ◽  
Cone Production ◽  
Seed Cone ◽  
Vegetative Bud ◽  
Needle Primordia

Black spruce (Piceamariana (Mill.) B.S.P.) grafts growing in a seed orchard were sprayed with gibberellin A4/7, and grafts and trees in families growing in arboreta were sprayed with gibberellin A4/7 and (or) vitamin E from vegetative bud burst to the end of shoot elongation. Gibberellin A4/7 was very effective in promoting seed cones and 400 mg/L appeared optimal. Vitamin E at 1000 mg/L was not effective. Vegetative bud burst occurred in mid-May and shoot elongation ended in late June. Needle primordia were visible on the apices of newly formed buds at the end of June. Reproductive buds had fewer bud scales than vegetative buds. It appeared that potential reproductive buds terminated their bud scale initiation earlier. Gibberellin A4/7 application to promote seed-cone production should be carried out before bud-type differentiation. This coincides with the end of lateral shoot elongation.

Cost of reproduction in Douglas-fir

1992 ◽  
Vol 70 (7) ◽  
pp. 1429-1432 ◽  
Author(s):  
Yousry A. El-Kassaby ◽  
Hugh J. Barclay
Keyword(s):  
Pseudotsuga Menziesii ◽  
Annual Ring ◽  
Ring Width ◽  
Energy Allocation ◽  
Douglas Fir ◽  
Environmental Correlations ◽  
Annual Ring Width ◽  
Trade Off ◽  
Cone Production ◽  
Seed Cone

The balance between allocating energy resources to reproduction or growth has considerable theoretical interest. Conflicting ecological requirements and evolutionary pressures often necessitate a trade-off in energy allocation. We obtained measurements on seed-cone production and annual ring width of 365 Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) trees from 29 open-pollinated families for 8 years. Phenotypic, genetic, and environmental correlations were computed for seed-cone production and ring width for each year. Five of the eight environmental correlations were negative (range −0.077 to −0.305), reflecting the reality of the trade-off in physiological terms. Six of the eight genetic correlations were negative (range −0.199 to −0.776), indicating that a trade-off exists at the genetic level between energy allocation to reproduction and to somatic growth. These findings agree with the current theory of life-history evolution. Key words: Pseudotsuga menziesii, cone production, annual ring width, genetic correlation.

A NEW TAXODIACEOUS SEED CONE FROM THE OLIGOCENE OF WASHINGTON

1989 ◽  
Vol 76 (1) ◽  
pp. 133-142 ◽  
Author(s):  
Charles N. Miller ◽  
David R. Crabtree
Keyword(s):  
Seed Cone

DEVELOPMENT OF THE SEED CONE OF DOUGLAS-FIR FOLLOWING DORMANCY

1965 ◽  
Vol 43 (2) ◽  
pp. 317-332 ◽  
Author(s):  
John N. Owens ◽  
Frank H. Smith
Keyword(s):  
Early Development ◽  
Maximum Size ◽  
Developmental Cycle ◽  
Surface Layers ◽  
Adaxial Surface ◽  
Single Leaf ◽  
Separate Branch ◽  
Cycle Growth ◽  
Seed Cone ◽  
Lateral Shoots

Development of the megasporangiate cone during the period of enlargement and maturation following dormancy is described in detail. This work, in conjunction with the early development previously described, provides a complete description of the 17 month developmental cycle. Growth of the megasporangiate cone is resumed in early March near Corvallis, Oregon, and the cone buds burst about 1 month later. The cone elongates rapidly by intercalary growth. Bracts enlarge but the shape of the bract established prior to dormancy is essentially maintained. The scale assumes a spoon-shaped appearance as a result of a form of marginal growth. Vascularization, and development of other tissues within the bract and scale, indicates that bracts are homologous to leaves and basically similar in structure, but scales are highly modified fertile lateral shoots. Each bract is supplied by a single leaf trace and each scale by two separate branch traces. The seed wings differentiate from adaxial surface layers of each scale. A large zone of macrosclereids differentiates in the basal abaxial portion of the scale. The cone reaches its maximum size early in July and maturation of tissues occurs in July and August, and is generally complete early in September. Cone opening results from drying and shrinkage of the macrosclereids at the base of the scale.

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