Botany Blog Plants of the Northeastern U.S.

July 16, 2021

Purple Bergamot: Hybrid or species?

Filed under: Uncategorized — admin @ 21:19

For a number of years I have been growing the two common eastern species of Monarda, M. didyma and M. fistulosa. Monarda didyma (scarlet beebalm or Oswego tea) is an important early summer food source for ruby-throated hummingbirds. It begins flowering in late June but continues into July.

Flowers of Monarda didyma being visited by a male ruby-throated hummingbird
Flowers of Monarda fistulosa

The flowering period overlaps with the start of flowering of M. fistulosa (wild bergamot) so there is opportunity for hybridization between the two species. Their preferred habitats, however, differ quite a bit. Monarda didyma tends to prefer moist alluvial soils and is often found in moist woods or thickets, along streambanks, or the shaded margins of wetlands. Monarda fistulosa tends to prefer somewhat drier habitats and is often found on hilltops, in meadows, or on dry gravelly river banks or shores. Those latter habitats, as well as human disturbance, have the potential to bring M. fistulosa into close contact with M. didyma.

Back to my garden, last year a Monarda appeared that has flowers that were intermediate in color and other characteristics between M. didyma and M. fistulosa.

Hybrid of M. didyma and M. fistulosa

The only explanation for these plants was that they were a hybrid of the two species and the characteristics seem to match the description of M. media in the literature.

M. didyma on the left, hybrid in the middle, and M. fistulosa on the right

Getting a little more specific, beyond the color there are some differences in the corollas of M. didyma and M. fistulosa. Monarda didyma has a corolla that is more than 3 cm long that is hairless on the upper lip.

Opening of the corolla tube. Note lack of hairs on the upper lip.

In contrast, the corolla tube of M. media and M. fistulosa is up to 3 cm long. In M. fistulosa the upper lip is bearded while in M. media it is glabrous or only sparsely hairy.

Corollas of M. fistulosa. Note bearded upper lip.
Corollas of hybrid. Note only a few hairs on the upper lip.

A number of papers have been published that propose that M. media is a hybrid of M. didyma and M. fistulosa (Egler 1973; Whitten 1981). The fact that these intermediate plants only seem to occur where the ranges of those two species overlap would seem to support that hypothesis. The habitat for M. media is said to be dry to moist open woods, fields, and roadsides, which is rather non-specific and could easily occur in close proximity to both putative parents. It has also been suggested that in the southern Appalachians what is called M. media may be the hybrid of M. didyma and M. clinopodia. While Monarda media is treated as a distinct, rare species in a number of states, very little information is available regarding existing populations that would provide support for recognition as a distinct species, e.g. population size, proximity to populations of M. didyma and M. fistulosa, how long these populations have persisted, ect. If Monarda media is a good species, then the name for the hybrid of M. media and M. fistulosa would be Monarda × mediodes (Duncan 1959), though some sources recognize both as hybrid taxa.

Literature Cited

Duncan, W.H. 1959. A naturally occurring F1 hybrid of Monarda media and M. fistulosa. Rhodora 61: 302-305.

Egler, F.E. 1973. The hybrid nature of “Monarda media Willd.” Castanea 38(3): 209-214.

Whitten, W.M. 1981. Pollination ecology of Monarda didyma, M. clinopodia, and hybrids (Lamiaceae) in the Southern Appalachian Mountains. American Journal of Botany 68(3): 435-442.

July 15, 2020

Geum aleppicum × canadense

Filed under: Uncategorized — admin @ 12:03

This rare hybrid has been reported in the literature a few times but has never been given a formal name. To see for myself what it looks like, a couple years ago I manually deposited pollen from Geum canadense onto several flowers of Geum aleppicum at a site where both occur. I marked the flowers that had been pollinated and returned later in the season to collect seeds.

I was able to grow out about 30 plants from the seeds and at the end of June of this year they finally bloomed. While the majority of plants appear to be straight G. aleppicum, one plant is an obvious hybrid. Success!

Overall the plants are most similar to G. aleppicum but with paler flowers that begin flowering around the same time as G. canadense (G. aleppicum starts flowering slightly earlier). Also notice that the petals are a bit more slender than is typical of G. aleppicum.

The following image shows the fertile fruit of G. aleppicum (left) and the sterile fruit of G. aleppicum × canadense (right). Geum hybrids are typically sterile, one exception being the hybrid of G. rivale and G. urbanum (G. × intermedium).

The foliage of the hybrid is similar to Geum aleppicum but the upper leaves are less divided. They are also not as dark green. It remains to be seen if they will darken when dried, a characteristic typical of G. aleppicum.

This last image shows the flower of the hybrid (middle) with flowers of the two parents, G. aleppicum (left) and G. canadense (right).

September 9, 2019

Hibiscus

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Several years ago I started unknown Hibiscus from seed assuming it would be H. moscheutos. Each year the plants would grow about 5 feet tall but never flowered. One finally flowered this year and something seemed a bit odd about it. I believe it Hibiscus laevis, a related species with narrower, often hastate leaves that are smooth on the lower surface, and flowers with darker red centers. Would include a picture of the leaves but they have been badly eaten by caterpillars.

Just happened to pass a large population of Hibiscus moscheutos a couple days ago so I made a run out to get photos of the real thing. This species has more solid pink flowers, wider leaves, and the leaves tend to have a fuzzy pubescence on the lower surface. Otherwise it is very similar and has a range that extends further into the Northeast.

May 20, 2017

Cecropia

Filed under: Plant-Insect Interactions,Uncategorized — admin @ 15:21

Cecropia moths (Hylaphora cecropia) have started to emerge from their cocoons. Here is a caterpillar in its fourth and final instar toward the end of August of last year.

And this is what they look like after cocooning. The leaves are maple leaves, one of the primary food plants of the caterpillars.

Mating adults after their wings expanded in May.

May 2, 2015

Trailing arbutus and twinleaf

Filed under: North American Native Plants,Uncategorized — admin @ 18:12

Trailing_arbutus

Trailing arbutus (Epigaea repens) has just started blooming in Central NY. It is a member of the Heath Family (Ericaceae) found in semi-open areas on acidic, mesic to dry, sandy or gravelly soils. It seems to prefer slopes, perhaps because on level ground the evergreen leaves would otherwise covered by falling leaves from the canopy above. It can be locally abundant and has a NY state rank of S4.

Jeffersonia_diphylla
Twinleaf, (Jeffersonia diphylla), is also flowering now. It is most common in west central NY and is listed as threatened in the state (S2). The genus is named for our third president.

February 28, 2011

Herbarium sheets: lessons from the past

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I am in the process of digitizing and cataloging the vascular plant specimens housed in the herbarium at SUNY Cortland. Some of the specimens were not mounted properly or demonstrate other issues that may not have been obvious to the collector at the time. The purpose of this article is to describe a few of these issues and explain how to avoid them to improve the longevity of mounted plant specimens.

A standard herbarium sheet is 11.5 x 16.5 inches. Larger sized sheets do not fit properly into a folder and are prone to damage, and are also prone to damage other specimens as they jostle the other contents of the folder in which they are stored.

A 100% rag content sheet is optimal but 25-50% rag paper can be used. Of greatest importance is that it be acid-free. Not only will an acid paper deteriorate over time, but it will also damage any specimens that it comes into contact with. Below is an example of such a sheet that was damaged by a smaller sheet placed on top of it. You can see the damage as a darker rectangle in the lower left of the sheet.

Damaged herbarium sheet

Another problem with some of the specimens was the use of inappropriate mounting materials like scotch tape. The degree of deterioration varies. The plastic tape used to affix the label on the specimen below can be seen to have degraded badly and darkened the paper of both the herbarium sheet and label to a large extent.

Aged plastic tape

If tape is to be used to help fix the specimen to the sheet it should be acid-free gummed linen tape. Some art suppliers carry this archival tape. Only thin strips are used and potentially the tape could be removed at a later date by re-softening the adhesive with water. The following image shows the tape used to mount a specimen that is now over 100 years old. As you can see it is still in excellent condition, however the paper on which it was mounted was not of the best quality so it has darkened quite a bit.

Properly mounted specimen

A final note regarding adhesives. The one most often used is polyvinyl acetate glue like “white glue” (Elmer’s). White glue is sensitive to heat and moisture and will degrade in UV light, but these should not be an issue in a properly maintained herbarium. I have found that when other, unknown adhesives had been used that they had turned brown, became brittle, and the specimen or label it was used to mount had fallen off. When using white glue it is usually diluted with a small amount of water (less than the amount of glue or it will be too thin), and dabbed gently onto the specimen with a paintbrush. After gluing the specimen and label onto the paper the entire sheet should be covered with wax paper and gently pressed and left to dry overnight. The latter step assures the best contact with the sheet and keeps the specimen and paper from curling as it all dries. Bulky specimens can be further reinforced with a little thread sown through the paper and around the stem. As evidenced by the plants in our collection a properly mounted a specimen will last for at least a century.

And don’t forget to include relevant information on the label. I have come across far too many specimens lacking dates and complete location information. Without these a specimen is largely useless for scientific study.

December 22, 2010

Christmas Cactus and Christmas Fern

With Christmas just a few days away I figured it would be a good time to discuss some of the plants often associated with the holiday. Besides trees, probably the one that most often comes to mind is the poinsettia (Euphorbia pulcherrima). The poinsettia is native to Mexico and South America. It is a member of the spurge family (Euphorbiaceae), many members of which produce milky latex sap and showy bracts (modified leaves) that surround one or more floral structures called cyanthia. A cyanthium is composed of a single female flower partially surrounded by a cup-like involucre topped by five simplified male flowers. In the poinsettia the cyanthia are yellow-green and the floral bracts resemble the leaves but are large and scarlet red.

A long-standing myth is that the poinsettia is poisonous due to the death of a 2 year old child in 1919 that was falsely attributed to ingestion of this plant.  While the plant is not considered edible, the toxicity of the plant is quite low and at worst it may cause upset stomach or vomiting if eaten.

Another popular plant this time of year is the Christmas Cactus, which is actually represented by a few species mostly in the genus Schlumbergera. In the wild they are epiphytic cacti, growing on trees in forests of South America. What appear to be leaves are actually flattened stems. Sections of the stem root easily in a loose potting mix that includes a good proportion of sand. Flowering is triggered by short days and long nights, as is the case with poinsettia. While I don’t have any pictures of the latter, I did manage to find a few pictures of a Christmas Cactus in bloom.

xmas_cactus1.jpg

Christmas Cactus

xmas_cactus3.jpg

I will end this with a perhaps less commonly known plant associated with the holiday, and one that is native to Eastern North America. The Christmas Fern (Polystichum acrostichoides) is so named because it was once popular for use in Christmas decorations due to its tough, evergreen leaves that can be found throughout the year, even under snow. It grows on well-drained soils in rich, shady woodlands.

Christmas Fern

July 18, 2010

Bittersweet Nightshade

Filed under: Naturalized Plants,Uncategorized — admin @ 19:12

Bittersweet Nightshade (Solanum dulcamara) is an herbaceous vine in the potato family (Solanaceae). It is native to Eurasia but has naturalized widely in North America. It occurs in a variety of habitats provided sufficient light is available. Several features aid in identification. First are the purple flowers with five reflexed petals and bright yellow stamens

Bittersweet Nightshade Flowers

The fruit matures from green to yellow, orange, and finally bright red and resembles a small tomato (also in the potato family). The plant gets its name from the reputed taste of the fruit, which is said to be bitter at first but later sweet. While the fruits are said to be less poisonous than the rest of the plant, I have never dared to taste one as all parts of the plant contain solanine which is extremely toxic. While poisonings are rare, fatalities have been known to occur.

Bittersweet Nightshade Fruit

The leaves are somewhat arrow-shaped and often have two or more lobes at the base. The color is dark green and they seldom have evidence of herbivory. The smell of the leaves is perhaps this plant’s most distinguishing characteristic, similar to tomato but much more foul and disagreeable. This trait has come in handy when it has been necessary to identify seedlings in the field.

Bittersweet Nightshade Leaves

July 5, 2010

Sedges

Filed under: North American Native Plants,Uncategorized — admin @ 22:20

Study plants for any length of time and one will eventually hear the phrase “sedges have edges”. This is because the stems of sedges typically have three angles, distinguishing them from the terete (round in cross-section) stems of grasses. For quite some time that was about the extent of my knowledge of this group of plants. A few years ago I decided to get serious about learning sedges, particularly the species rich genus Carex. One characteristic of plants in this genus is that the achene (seed) is surrounded by a sac known as a perigynium (plural perigynia). Close examination of these structures and the scales subtending them is often key to proper identification of plants in this genus. The perigynia are relatively large and inflated in Shining Bur Sedge (Carex intumescens), shown below.

Shining Bur Sedge

Recently I have been adding photographs and descriptions for Carex species to my Plants of the Northeastern U.S. website. One goal has been to document important details of the inflorescence using a dissecting scope including a ruler marked in millimeters. Recently added pages include those for Carex brunnescens, C. debilis, C. deweyana, C. disperma, C. hystericina, C. interior, and C. radiata.

June 27, 2010

Poison Hemlock

Filed under: Naturalized Plants,Uncategorized — admin @ 19:40

Poison hemlock (Conium maculatum) is a biennial herb that can grow to 3 m tall. It has a smooth stem that is often purple-streaked or spotted. The leaves are broadly triangular and divided into 3-4 segments with finely divided leaflets.

Poison Hemlock Leaves

The white flowers are produced in umbels up to 6 cm wide and rather resemble a large Wild Carrot (Daucus carota).

Closeup of Poison Hemlock Flowers

This species is native to Eurasia but has been introduced and has spread widely throughout North America. Most often found in partially shaded, disturbed areas on soil ranging from dry to wet, it is perhaps best known as the plant given to Socrates after he was sentenced to death. All parts are extremely poisonous but the parts of the plant that are most toxic are the seeds and root.

Poison Hemlock Flowers

 

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