How to Identify Plants

After a visit to the poison garden, it is obvious that being able to identify plants is an asset. Today’s resource is a little book called How to Identify Plants, by H.D. Harrington. The book is published by Swallow Press books (Ohio University Press), with copyrights in 1957 and 1985; and illustrated by L.W. Durrell. Harold David Harrington (1903 - 1981) was a professor of botany and zoology at Colorado State University from 1944 through 1968, and the curator of the CSU Herbarium for 25 years. Harrington was an expert on edible and poisonous plants, grasses, and aquatic plants in Colorado and the West, and authored several books. His wife, Edith, was also a botanist, and assisted him with his specimen collecting forays and manuscripts. Two species are named in his honor – Penstemon harringtonii and Oenothera harringtonii.

The initial chapters describe why it is important to identify plants, and how plants are classified and named. The bulk of the book defines terms relative to plant parts, including the flower, inflorescence, underground parts, stems, leaves, fruits and seeds, and surfaces. Many illustrations enhance the definitions. Additional chapters provide helpful reference material, such as how to use keys to identify plants, how to collect and press plants, and what regional manuals and floras are available. The glossary provides access to the terms in alphabetical order.

This is a great book for beginners just learning the language of plants, and for experienced plant lovers who need a quick reminder of how to describe a leaf shape, or flower construction. The book is small enough to toss in a day pack, or keep on your desk.

Poison Gardens – Water Hemlock

Water hemlock (Cicuta douglasii) is a flowering perennial herbaceous plant in the carrot family (Apiaceae). The United States Department of Agriculture (USDA) considers water hemlock the most poisonous plants in the Western United States, with a range from Alaska to California. Several other plants may be mistaken for water hemlock, including poison hemlock (Conium maculatum – used in the poisoning death of Socrates), wild parsnips, and other herbs or perennial plants).

Water hemlock. Photo by Barry Breckling, used under Creative Commons Attribution-NonCommercial-ShareAlike 3.0 (CC BY-NC-SA 3.0) license.

The heavy scented plant grows up to 8 feet tall (2.5 meters), with a sturdy, hollow stalk; small white flowers in terminal compound umbels; leaves decompounded (side veins lead to notches, not to tips, at the outer margins); poisonous roots; and slightly flattened fruits.  The thick rootstalk includes several chambers containing the poisonous compound cicutoxin, which is an unsaturated aliphatic alcohol (although all parts of the plant are poisonous).

 Cicutoxin works on the central nervous system. Symptoms include nervousness, excessive salivation and frothing, muscular twitches, dilation of the pupils, rapid pulse and breathing, tremors, violent convulsions, and death from asphyxiation and cardiovascular collapse. A very small amount can cause death in people, pets, and livestock. Contact a poison control center immediately if symptoms occur.

The plant is found in riparian areas, near stream banks, bogs, and marshy areas. It can be used in a wild or bog landscape, but may not be an appropriate choice for small children, pets, or livestock.

Poison Gardens – Purple Nightshade

A couple of years have passed since we last visited the poison garden (California Buckeye, Poison Oak, and Stinging Nettle). Halloween seems the perfect time for another foray! Many plants in the San Francisco Bay Area have some level of toxicity, enabling them to fend off predators.

Purple nightshade (Solanum xanti) is a perennial, flowering, evergreen shrub that is native to the Western United States, including California. It grows to 35 inches high, with a hairy stem; leaves that are lance shaped to oval, somewhat lobed, and 2 - 3 inches long; a distinctive umbel-shaped inflorescence with purple-blue flowers up to an inch and half wide; and a green berry fruit that is ½ - ¾ inches wide. Nightshade can thrive in a variety of environments, including chaparral, conifer forests, and oak woodlands.

Purple Nightshade (Solanum xanti) - photo by Dawn Endico,
taken on Mitchell Canyon trail, Mt. Diablo, Northern California. (Jepson)

 

Nightshade is toxic, as are other members in the Solanaceace family. All parts of the plant are poisonous, especially the unripe fruit. Toxicity is from Solanine and glycol-alkaloids, chaconine, and solasodine. There is no antidote for Solanum poisoning. Symptoms include:

• Cardiovascular system (tachycardia, arrhythmia, and hypotension)
• Central nervous system (delirium, psychomotor, agitation, paralysis, coma, and convulsion)
• Gastrointestinal track (nausea, vomiting, diarrhea)

The plant is desirable in the landscape, as it is drought-tolerant, tolerates clay soil, grows under native oak, is deer resistant, and commonly blooms from January to May. Since the plant is poisonous, it may not be an appropriate choice for small children or pets.

Spiral Nematodes

Nematodes can be a threat to turfgrass, and have been found in golf courses, parks, and lawns in the San Francisco Bay Area. Spiral nematodes (Helicotylenchus spp.) are one of many nematode species that are found in the soil. Spiral nematodes have a wide host range, and do not cause excessive damage, but they can reduce the vigor of plants in a monoculture host like turf grass. Mature spiral nematodes are up to 1.2 mm long, and are so named because they curl up into a spiral when dead or relaxed. They are ectoparasites, meaning they feed outside the cell, although some may act as partial endoparasites—inducing growth of a food cell in which they bury their head to feed for long periods of time, before moving on to create a new food cell. These food cells do not grow like a gall, but the cell composition does change.

Spiral nematodes are all females, reproduce without mating, and lay individual eggs in the soil (unlike the root rot nematode that lays an egg mass). The first molt occurs within the egg (J1). If moisture is present in the soil when the egg hatches (J2), the nematode is motile and works its way to a plant root where it can feed. The nematode undergoes three more molts (J3 and J4), before becoming a mature adult. Populations are highest in late summer and early fall and lowest in spring when cold temperatures inhibit reproduction.

Spiral nematode turf damage is associated with bluegrass and Bermuda grass. Above ground symptoms include stunting, reduced plant vigor, yellowing or brown patches in the turf, and areas that succumb to weeds. There is typically a “hot spot” or dead zone, which is heavily infested. These symptoms can have other causes, so soil analysis is required to diagnose the problem: http://youtu.be/taW-VM-4IRw

For management tips, see the Integrated Pest Management(IPM) site. Prevention is the best approach, but strategies like crop rotation are difficult for turf. Chemical treatments exist, but some of them cause damage to turf, or must be repeated, since they also kill beneficial organisms that keep other diseases at bay. See UC IPM Pest Management Guidelines: Turfgrass (page 72) for additional information.

Root Rot Nematodes

Root-rot nematodes are from the genus Meloidogyne, and thrive in hot climates with short winters. They are not host-specific, and infect the roots of a wide host range, including flowers and vegetable crops (tomato, green pepper, corn, grains, and so forth). They are sedentary endoparasites—living and feeding from within their hosts.

Females lay their eggs in a gelatinous mass on a root gall surface; ensuring a protective, moist environment in which the eggs develop. The first molt occurs within the egg (J1 stage). After the eggs hatch, the second-stage juveniles (J2) are motile. They leave the egg; penetrate the root with their stylets, just behind the root cap; and secrete a liquid that stimulates growth hormones in the cells, causing them to divide and swell. This forms root galls that become permanent feeding sites. After molting through two more juvenile stages, (J3 and J4), reproductively mature females lay a new batch of eggs. This lifecycle occurs over the course of several weeks, so, in the right environmental conditions, plants can become infected very quickly. If the galls become separated from the roots, the eggs can exist in the soil for years, until the right conditions and a suitable host are available.

Galls on carrot from root-rot nematode. Photo by Claudia Nischwitz.
Copyright, ASPnet.

Above ground, plants exhibit symptoms that are similar to any disease that harms the root system, including stunted growth, wilting, and yellowed leaves. Reduced crop yield also results. To help with diagnosis, it is necessary to have the soil analyzed and to check the roots for galls, if at all possible.

For management tips, see the Integrated Pest Management (IPM) site. Since the eggs can remain in the soil for years, management is difficult. The solution is prevention – using resistant plant varieties; rotating crops so the nematodes cannot continue their lifecycles from season to season; leaving soil fallow periodically; amending the soil to keep it healthy; planting when nematodes are less active; and keeping infected plants or material from contaminating uninfected areas. Soil solarization, the process of heating the top 8 - 12 inches of the soil, can temporarily reduce the nematode population. Currently no chemical or soil fumigants are available to the home gardener.

Plant Diseases - Nematodes

This time I’m researching nematodes, which are non-segmented round worms found in soil, water, and extreme environments such as deserts and ice fields. A few can be seen with the naked eye, but most are tiny and require magnification. For resources I’m using Essential Plant Pathology, information from my plant diseases course at Merritt College in Fall 2012, and Five Kingdoms. Keep in mind that most nematodes are beneficial – they aerate the soil, consume detritus, feed on bacteria and other small life forms, and circulate organic and mineral soil components. Others cause considerable damage to crops, turf, and plants in the landscape. Nematodes can be found in the San Francisco Bay Area.

Nematodes are categorized as Eukarya in the Animalia kingdom. About 10% of all nematodes are plant parasites, and require a living host (obligate parasites). They are aquatic and typically live, feed, and move in the soil. They use a specialized feeding structure—called a stylet—to penetrate plant tissue, probe, secrete proteins and polysaccharides, and ingest cellular contents. Most nematodes are migratory and move from cell to cell to feed (ectoparasites). Others are sedentary and remain embedded in a plant throughout their lifecycles (endoparasites); some endoparasites induce formation of specialized feeding sites, such as galls, where they live and feed. A few do not fit either of these categories.

The female nematode lays hundreds of hardy eggs (some species do not require male fertilization of the eggs). The eggs can exist in soil for years or decades, until the right environmental conditions exist for them to infect a plant. Their life cycle includes four juvenile stages. Nematodes molt, shedding the outside cuticle and part of the lining of the stylet, from stage to stage as they grow. Juveniles look like miniature adults through all stages (they do not undergo a metamorphosis from stage to stage).

Take a look at several nematodes; of special interest (1) views of the stylet at 57, 107, and 145 seconds, (2) a root rot nematode at 159 seconds, and (3) a needle nematode at 202 seconds: http://youtu.be/Qf8oGjqyXFc

On the Roof at MOMA

I am always on the lookout for roof top gardens. They can be elaborate and extensive, or a quiet and private space. On one of our son’s visits home from University of Alaska, Anchorage, we visited the San Francisco Museum of Modern Art (or MOMA) to view their art collection. The building was designed by Jensen Architects (an international firm based in San Francisco), and is very distinctive.

One of the fun discoveries was the Carolyn and Preston Butcher Garden Terrace, with its roof top sculpture garden and small coffee bar. We spent part of our MOMA visit on the roof, enjoying the combination of closed and open air space, and interesting sculptures. I also enjoyed the chance to study the raised planting areas and choice of vegetation. It was simple, yet very satisfying.

Carolyn and Preston Butcher Garden Terrace (MOMA) - raised bed

The museum closed earlier this summer for a three-year renovation project. See their web site for information about their off-site exhibition this fall (http://www.sfmoma.org/). You can catch a glimpse of the Garden Terrace in the short video “Trailer for Stories from the Evacuation” (fast forward to 1:11).

Clear Lake Plant Diseases

I’m afraid my Plant Diseases class from Merritt College in Oakland has despoiled me – I am always on the lookout for plant diseases! End-of-summer is a great time to spot them, as many plants have spent their reserves on reproduction, and are more vulnerable to attack. Here are some of the diseases I spotted in Clear Lake; oaks seem especially hard hit.



Sudden Oak Death –  I wasn't close enough for direct inspection, but this looks like SOD from afar; caused by the water mold, Phytophthora ramorum. 

Oak Gall – these little "nipples" are galls caused by asexual reproduction by the oak gall wasp.
When the wasp lays its eggs, hormones kick off a type of genetic engineering to create the perfect nursery (the gall).

Oak Apple Gall – this "strange fruit" indicates sexual reproduction by the oak gall wasp.

Tent Caterpillar – we found these gauzy structures all over foliage.
The residents had already moved on.

In many cases, these diseases do not cause permanent damage. An organism is simply taking advantage of a situation, and working through its own life cycle. After the class, seeing plant disease is not necessarily alarming. Plants in nature are rarely perfect; instead, they are teaming with all sorts of life forms. Learning to enjoy the whole ecosystem of a plant, both good and bad, can add to the enjoyment of nature as well as the garden. And raising your tolerance for imperfection can lower the need to combat the imperfect with pesticides.

Clear Lake Wine Country

We visited several wineries in Clear Lake, and learned all about the wonderful soil, enriched with age-old volcanic ash, and the excellent climate and growing conditions. One especially interesting winery is Ceago Vinegarden Wineries, created by Jim Fetzer (formerly of Fetzer Vineyards), near Nice on the north end of Clear Lake.

Ceago Winery from the dock – lavender

Ceago is a certified Biodynamic winery that uses organic, sustainable, and earth-friendly practices, designed to produce a top grade product and rejuvenate the earth. Their practices include crop rotation; composting; use of, manures, green manures, and organic fertilizers; and avoiding genetically engineered organisms and chemical pesticides. Ceago specializes in both red and white wines, and also grows organic vegetables, and lavender for its essential oils.

Shady arbor

We had a great visit to Ceago. We arrived by boat, so approached the winery from Clear Lake. The lavender had recently been harvested, so the remaining plants were a dusty gray green and clipped into rounded shapes (it must be beautiful when the plants are in full bloom). The buildings and grounds are lovely and well kept, with restaurant, tasting room, and small store centrally located in the main building. The landscaping includes a central courtyard, a leafy arbor, and vegetable garden.

The dock