| BEN |
| BOTANICAL ELECTRONIC NEWS |
|---|
| ISSN 1188-603X |
| No. 468 June 6, 2013 | aceska@telus.net | Victoria, B.C. |
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From its beginning in spring 1991 until March 2013, BEN had only one major malfunction: BEN # 13 [are you surprised?] posted on October 14, 1991 triggered a mail storm and all the subscribers received that issue more than 30 times. I was surprised that not too many people unsubscribed.
In April 2013, I made two blunders at once. On April 1st I posted a regular BEN instead of the traditional April Fools' Day issue and many subscribers considered it to be an excellent joke. I apologize to all the BEN subscribers and to all the BEN # 466 contributors for this mistake. I felt embarrassed when some readers congratulated me to my sole authorship of the whole BEN # CDLXVI. They grossly overestimated my IQ.
Finally, on April 30, I overlooked that I sent my communication with Prof. Art Kruckeberg to the whole BEN mailing list. Art included the BEN-L mailing address into the cc: addresses and my "Reply to All" worked, as it should. This blunder had a positive aspect as well. I learned about an article that summarized Macoun's contribution to mycology and found several old BEN contributors from whom I have not heard for a long time. I apologize to all other BEN subscribers who might have been confused by that posting.
That was not the end. BEN server moved and BEN distribution list stayed behind. My BEN # 468 dated May 30, 2013, could not be posted until on the D-Day.
Among our most common rushes, in the genus Juncus, is J. tenuis Willd. (path rush). It is found on wilderness shores, prairie swales, potholes (both kinds), and in ditches. It comes up in wet cracks in the sidewalks of our cities, and on the muddy trails of moose on the Canadian border. Juncus tenuis is common in Washington's lakes, rivers, and marshes, and it is common across much of North America. One reason it is so widespread and frequently encountered is its production of a multitude of tiny seeds, half a millimeter long, that get sticky when wet and can hitchhike long distances on passing mammals, birds, and vehicles. And like many Juncus, path rush is not too fussy about where those little seeds will germinate. Seasonally damp and exposed mineral soil is a prime habitat, explaining why it is so common on so many active shorelines and wet roadsides.
Such a common plant should be pretty easy to identify, with so many sightings. But that is not the case. Path rush has a number of close relatives in the Pacific Northwest: Juncus anthelatus (Wiegand) R. E. Brooks (Kentucky rush); J. confusus Coville (Colorado rush); J. dudleyi Wiegand (Dudley's rush); J. gerardii Loisel. subsp. gerardii (mud rush); J. interior Wiegand (interior rush); J. occidentalis (Coville) Wiegand (prairie rush); and Juncus trilocularis Zika (foothill rush), a replacement name for what we used to call J. brachyphyllus (short-leaf rush). These slim plants are separated, with a bit of effort, by technical details of their auricles and ripe capsules. Many published photographs, floras, and botanists have the species confused. Together these inconspicuous rushes are thought of as the Juncus tenuis group and are classified in Juncus sect. Steirochloa, according to the excellent (but hard to find) worldwide monograph of the genus (Kirschner et al. 2002).
If you flip open your copy of Flora of the Pacific Northwest (Hitchcock & Cronquist 1973), you won't find all those rush names. That is the first part of the problem. However, they are accounted for in the Juncus treatment in the new Jepson Manual (Zika 2012a), which also has good keys for separating them, and is available online.
Sorting out Juncus tenuis from its cousins requires a hand lens and careful sampling. Although many keys to Juncus species (mine included) ask for stamen characters, enthusiastic students should not bother collecting flowering material with its anthers prominent. Wait for the plant to age and develop fully formed capsules with ripe seeds, which are critical for identification. The anthers will still be present underneath the tepals (petals or sepals) when the fruits mature. Another important point is to examine the foliage for the slender auricles at the junction of the leaf blade and stem. Because the leaves are attached quite close to ground level (perhaps an adaptation to resist grazing), a "top snatch" will not provide you with the auricles you need for identification. Most botanists do not realize that the auricles on the first fertile shoots of the year are typical, but they can be reduced and atypical later in the growing season, on late-developing shoots.
Finally, a bit of Juncus esoterica: the internal structure of the ripe capsules, which can be seen with a 10x hand lens, has three walls that intrude from the capsule perimeter. These walls bear the seeds. Some rushes, like J. confusus, are divided neatly into three segments by the walls, which meet in the center of the capsule and are united for their entire length along the central axis, except at the very tip. For these species, the seeds are contained in the three closed chambers. In longitudinal section, the chambers are shaped like the letter "D." Other species, like J. occidentalis, are built differently, with the three walls protruding only partway towards the center of the capsule. These walls are curved like the letter "C" and do not meet each other, except at the very base. This leaves the center of the fruit open. Seeds in these capsules can rattle around anywhere inside, because there is only one large chamber within. In the key below, these structures are referred to as "1-chambered" or "3-chambered" fruits, as illustrated by Catling and Spicer (1987).
1. Tepals black, tips blunt and curved inwards; usually in saline soils in coastal salt marshes .................. J. gerardii subsp. gerardii 1. Tepals green, brown, or red, tips acute or acuminate, erect to curved slightly outwards; usually in fresh water habitats 2. Auricles yellowed, thick and hard (like an old toenail), often shiny .......................................................J. dudleyi 2. Auricles dirty white or translucent, soft and thin, at least on the outer half (like cellophane), not shiny 3. Ripe fruits 3-chambered, the straight central axis united except at the tip 4. Styles elongate, 0.3-1.0 mm; tepals of different lengths, the petals (inner tepals) usually 0.4-1.0 mm shorter than the sepals (outer tepals); tepals green to pale brown ..J.trilocularis 4. Styles abbreviated, 0.05-0.2 mm; tepals more or less equal lengths, with deep brown stripes .............. J. confusus 3. Ripe fruits 1-chambered, the center open, with three curved partitions united only at the base 5. Capsule apex with ridges or crests, usually truncate or slightly notched ................................... J. occidentalis 5. Capsule apex rounded or with only weakly developed ridges, usually acute to blunt 6. Auricles < 1 mm long, rounded, thicker and opaque towards base, thinner and more translucent near outer margin; bracts at base of flower with long narrow tips (acuminate to aristate); stem with four to six well-developed longitudinal ridges ..................................... J. interior 6. Auricles usually 1-8 mm long (although shoots produced after midsummer have very short auricles), often acute to acuminate (though often blunt on late shoots), uniformly thin and nearly translucent; bracts at base of flower with acute tips; stem with or without well-developed longitudinal ridges 7. Common native with capsules usually >2.5 mm long; capsules usually more than 3/4 of the length of the tepals; fruits often overlapping to slightly congested on the inflorescence branches; stems generally lacking well-developed longitudinal ridges (rarely with 1 or 2 strong ridges) ................. ........J. tenuis 7. Rare introduction with capsules usually < 2.5 mm long; capsules usually < 75% of the length of the tepals; fruits widely spaced, not overlapping or congested on the inflorescence branches; stems with 2 to 6 well-developed longitudinal ridges ................... J. anthelatus
Juncus brachyphyllus (short-leaf rush) does not appear in the key. The species is found in damp ground in the Great Plains, from Nebraska to Illinois and Texas. It is entirely restricted to terrain east of the Rocky Mountains. Technical characters separate true J. brachyphyllus from plants of our region, west of the continental divide. The plants we called J. brachyphyllus in Washington have a new name, J. trilocularis, which is distinguished by the length of the style and anthers, and the striations on the stem (Zika 2012b).
In Washington J. trilocularis is found east of the Cascade Range, where it is uncommon below 1,500 meters elevation. I've seen collections from Garfield, Kittitas, Klickitat, Spokane, and Whitman counties. Juncus trilocularis is more frequent in southwestern Oregon, especially Jackson County, and in parts of northern California, such as Butte County. Its known range is from Washington to Idaho, south to western Nevada and central California.
In eastern Washington, Juncus trilocularis most closely resembles J. confusus. In addition to the key characters, they differ in their inflorescences. Juncus confusus tends to have congested or clustered fruits in a compact inflorescence, while J. trilocularis tends to have an open or loose inflorescence (Figures 2 & 3).
Several other species have a similar loose inflorescence like J. trilocularis; these include J. interior and J. dudleyi. Both differ in the details of their auricles, as described in the key, as well as their 1-chambered fruits. Neither Juncus interior nor J. dudleyi have fruits with strong crests or ridges on the summit. In its ridged fruit apex, Juncus occidentalis can resemble J. trilocularis, but J. occidentalis differs in having 1-chambered capsules. Juncus occidentalis is found no further east than Klickitat County in the Columbia River Gorge, while J. trilocularis ranges east to Idaho. For a map and for a much more detailed discussion of J. trilocularis, refer to the journal Rhodora (Zika 2012b).
I'd like to thank the Washington Native Plant Society Research and Inventory Committee for their generous support of the field work, herbarium research, and publication of this work. I'm also grateful to David Giblin and the herbarium staff at the University of Washington, who provided much time, facilitated loans, and allowed access to specimens and to their database.
Illustrations (http://bomi.ou.edu/ben/468/ben468.pdf) Figure 1. Juncus trilocularis Zika - Type specimen WTU # 389920 Figure 2. Juncus trilocularis - Infructescences of Zika 23932 Figure 3. Juncus trilocularis - Infructescences of Zika 25540
Bessette, A. E., A.R. Bessette, W.C. Roody, & S.A. Trudell. 2013. Tricholomas of North America: A Mushroom Field Guide The Corrie Hering Hooks Series Number 68. University of Texas Press, Austin, Tx. 220 p. ISBN 978-0-292-74233-8 (soft cover) Price: US$ 29.95
Tricholomas of North America is profusely illustrated and has enough detail in the text to be useful both to the amateur and the professional mycologist. Alan and Arleen Bessette and William Roody have been co-authors of several excellent field guides. The fourth author, Steven Trudell, is co-author with Joseph Ammirati of the successful Mushrooms of the Pacific Northwest. At 25.5 cm x 18 cm x 1.6 cm the Tricholoma guide is portable, and at under US$30 in paperback format, it is a bargain.
About 70 species have full macroscopic descriptions along with spore sizes and occasionally other microscopic details. Differentiating features from close species are noted. Almost 200 photographs are used in large enough format to retain their detail, two or sometimes three filling a page: they are both informative and aesthetically pleasing. Fifteen of these photographs show Tricholoma taxa that are not nameable. A key at the front of the book divides the species first by region and color, an approach which has shown itself to be useful for Tricholoma in the field. Filling out the 220 pages are discussions of history, concepts, ecology, edibility, useful features for identification, and excluded species. There is a glossary and a list of references.
I was eager to buy Tricholomas of North America to help sort out Tricholoma species in the Pacific Northwest. Pacific Northwest mycologists have had difficulty over the last thirty years in disentangling the various complexes (T. pessundatum s.l., T. terreum s.l., etc.) and deciding whether taxa we observe here are the same as the ones in Europe. It was too much to ask. Nevertheless, the authors did a reasonable job of summarizing the present state of knowledge, and the book will help many of those engaged in furthering that knowledge.
From the Preface: "...we recognize that this book represents only a first effort to describe and illustrate the tricholomas of North America and that it unavoidably will contain information that will require revision in the future." - See more at: http://utpress.utexas.edu/index.php/books/bestri#sthash.23udaGuf.dpuf
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