UPCOMING CHANGES in FLOWERING PLANT FAMILY NAMES: THOSE PESKY TAXONOMISTS ARE at IT AGAIN! by Ellen Dean

Home , Arthur Cronquist, Asclepias solanoana, Calycanthaceae, Cymodoceaceae, Fagales, Hydrangeaceae

In the new classification system, the milkweed family, Asclepiadaceae, will be placed in the dogbane family, Apocynaceae. The prostrate milkweed ( Asclepias solanoana) from Sonoma County is shown here. Photograph by J. Game.

UPCOMING CHANGES IN FLOWERING PLANT FAMILY NAMES: THOSE PESKY TAXONOMISTS ARE AT IT AGAIN! by Ellen Dean

e had a sense that be- low herb) and relatives. The name If one examines the name loved plant names were Epilo bium canum was used for Cali- change section of The Jepson Manual Wat risk when the scien- fornia fuchsia in The Jepson Manual (Appendix III), one finds hundreds tific name of one of our favorite of Higher Plants of Californ, iwahich of name changes that were incor- species, Zauschneria californic(aC ali- was published in 1993, and that name porated in the 1993 publication. fornia fuchsia), became Epilo bium change had plenty of company. For (See Skinner and Ertter, 1993, for a canum. That change was suggested example, the generic names of many discussion of this topic with regard more than 25 years ago in the mid- of the species of Orthocarpu s(owl’s to rare plants.) Nearly 10 years af- 1970s when Peter Raven, the cur- clover) morphed into Castilleja or ter the arrival of The Jepson Manual, rent director of the Missouri Bo- Triphysaria, while all of our Stipa some of us are still reeling from the tanical Garden, reexamined the species (needle grass) took on other loss of Matric aria matric ario idesthe, relationships among Epilo bium (wil- generic names, such as Nassella. old name for pineapple weed. (What

VOLUME 30:2, APRIL 2002 FREMONTIA 3 a wonderful name; somehow Chamomilla suaveolen wills never CLADISTICS, CLASSIFICATION, AND NAME quite do.) I imagine there are Cali- fornia botanists who don’t want to CHANGES OR TREES THAT HAVE PLANT see more name changes any time NAMES AT THE ENDS OF THEIR BRANCHES soon, am I right? Unfortunately, when it comes lassification is a basic hu- When put together, these two to plant taxonomy and classification, Cman endeavor; people clas- words are called the species name more changes are imminent, and sify tools, food, and telephone (ex. Quercus alb)a. For convenience, these are far reaching, often affect- numbers. Our classifications are Linnaeus placed the species he de- ing the families we have all known often hierarchical, that is, they scribed into classes based on sta- and loved for centuries. In a paper are nested subsets which may men type, arrangement, and num- titled “An ordinal classification for be visualized as venn diagrams ber, which meant that his classes the families of flowering plants,” (Figure 1) or written out as a often consisted of unrelated genera which was published in the fall of hierarchical list (Table 1). Plant and species. His revolutionary in- 1998 by the Angiosperm (flowering classifications using common novation was that he provided a ru- plant) Phylogeny Group (APG), a names are mainly made up of dimentary identification key to the group of 28 authors proposed a new folk genera such as “oak” or correct class—a huge help in orga- classification system for flowering “maple,” and folk species such nizing the increasing number of plants. The APG system is now be- as “coast live oak” or “big leaf plants that were being collected ing taught in college taxonomy maple,” although other catego- around the world. courses, thanks to the publication ries like “live oak,” “shrub,” or Linnaeus’s classification system of Plant Systematics: A Phylogenetic “tree,” may also be used. was replaced by plant classifications Approach, an excellent new plant sys- By the 16th century, Euro- that were based on presumed rela- tematics textbook by Walter Judd peans had begun the task of clas- tionships between species. At first et al. (2002). This text incorporates sifying every plant and animal in these classifications—which were much of the classification put forth the world by giving them a based on as many characteristics of in the APG paper, although it has a unique Latin description. In his the species as possible—were at- few surprises of its own. 18th century works, Carolus tempts to understand the order of For those of us who learned Linnaeus was the first to popu- nature or the plan of a creator. How- the flowering plant classifications larize a Latin description con- ever, by the end of the 19th cen- of Arthur Cronquist, Armand sisting of only two words, which tury, scientists began to incorpo- Takhtajan, or Robert Thorne when have become known as the ge- rate the notion of evolution into we took plant taxonomy in the 1970s nus name (e.g., Quercu,s the Latin classification systems. or 1980s, this new classification sys- common name for oaks) and its The term “phylogeny” was tem may come as a bit of a shock. modifier, the specific epithet coined to mean “evolutionary his- Most articles and books published (e.g., alba, Latin for white). tory,” and a “phylogenetic classifi- in this country over the past 20 years (including The Jepson Manua)l have followed Cronquist’s familial TABLE 1. SIMPLIFIED CLASSIFICATION classification. As with most flower- OF SIX SPECIES OF CALIFORNIA ing plant classification systems CONIFERS VIEWED AS A HIERARCHICAL produced during the 20th century, LIST Cronquist divided the flowering plants into a nested hierarchy of Pines Foothill pine (Pinus sabiniana) groups arranged to reflect an Sugar pine (Pinus lambertiana) approximation of evolutionary relationships. (See sidebar on pages Firs Silver fir (Abies amabilis) 4–7 for a more in-depth explana- Red fir (Abies magnific)a tion of classification.) He proposed two classes: the Spruces Sitka spruce (Picea sitchens)is monocotyledo ns(grasses, lilies, and Brewer spruce (Picea brewerian)a their allies, all of which have one seedling leaf or cotyledon), and the dicotyledon (fslowering plants with two

4 FREMONTIA VOLUME 30:2, APRIL 2002 did not become popular until the 1980s. Late in the same decade, the use of molecular data to de- termine relationships between species became commonplace. Scientists now sequence genes to look at the pattern of bases in DNA strands. Patterns between species are compared and analyzed using computerized cladistic analyses or other methods of phylogenetic reconstruction. Well-studied morphological features can also be added to the analyses, and the resulting phylogenetic trees are studied to de- termine relationships among species, genera, and families. Figure 1. Simplified classification of six species of California conifers viewed as a Venn Current classifications based diagram. on cladistic analyses only recognize monophyletic groups of or- cation” became one that placed spe- ing point (a putative ancestor) and ganisms (genera, families, or- cies, genera, or families together all the descendants above that ders). For example, recent clas- based on presumed evolutionary branching point is termed a “mono- sification systems recognize the relatedness. By the early 20th cen- phyletic group.” One example is the flowering plants (angiosperms) tury, some classifications included Fagaceae family, which are shown and monocotyledons, because drawings of evolutionary trees il- in Figure 2, although not all genera they form strong monophyletic lustrating the author’s hypothesis in the family are shown. groups in cladistic analyses (Fig- of ancestor descendant relationships The use of cladistics in taxonomy ure 3). These groups are not only among the flowering plants. These were called “phylogenetic recon- structions” or “phylogenetic trees.” In the 1950s, Willi Hennig, a German entomologist, began a school of phylogenetic reconstruction called cladistics. The output of a cladistic analysis is a cladogram, a type of phylogenetic tree. The ma- jor contribution of cladistics is the explicit understanding that related species should be grouped based on shared features that are “derived” or different from those possessed by an ancestral population. These shared derived features are termed “synapomorphies.” For example, the scaly cupule (acorn cap) found in all members of the oak family (Fagaceae) is a mor- Figure 2. Hypothetical simplified phylogenetic tree of two California plant families phological synapomorphy for that in the order Fagales (not all families and genera are shown). Unifying synapomorphies family (Figure 2). A cluster on a that group members of the Fagales and members of the Fagaceae are indicated on cladogram that includes a branch- the branches.

VOLUME 30:2, APRIL 2002 FREMONTIA 5 Figure 3. Simplifed phylogenetic tree of seed plants with key synapomorphies indicated on the branches. The innovation of one cotyledon unites all monocotyledons into a monophyletic group. As can be seen from this tree, most seed plants have two cotyledons, therefore the presence of this feature in dicotyledons is an ancestral (not a derived) feature. The dicotyledons, therefore, are not a monophyletic group.

supported by molecular data, elimination of these groups is one branches. The most parsimoni- but they are defined by impor- reason for the current reshuffling ous tree, however, is not neces- tant morphological synapomor- of genera and families. sarily the true evolutionary tree. phies—the ovary in the case of Cladistic analysis and other Therefore, as more information the angiosperms, and one coty- types of phylogenetic reconstruc- is obtained over the next few ledon in the case of the mono- tion are not perfect, however, be- decades and new and better cotyledons (Figure 3). cause different genes or other char- forms of analyses are employed, In contrast, current classifi- acteristics may provide apparent the classification of flowering cations do not recognize the di- conflicting synapomorphies, pro- plants will continue to change. cotyledons (flowering plants with ducing different phylogenetic trees. Unfortunately for all of us, two cotyledons, the members of In these cases, it is assumed that when classifications change, which are outlined in Figure 3), some such features evolved more sometimes plant names change. for it turns out that the posses- than one time or evolved and then Why is this? The naming of plant sion of two cotyledons is not reverted to a previous form. groups is guided by an interna- novel within the flowering plants; To choose among the hundreds tional body of taxonomists and having two cotyledons is an an- of trees that may be produced by a a document called the Inter- cient feature that most seed plants large analysis, the principle of par- national Code of Botanical No- share. Cronquist’s classification simony is employed. The most menclature (ICBN) which is up- recognized many non-mono- parsimonious tree is the shortest dated every five or six years. The phyletic groups that were based tree, requiring the fewest changes Code specifies that every species on shared ancestral features. The in characteristics along the tree name be tied to a particular her-

6 FREMONTIA VOLUME 30:2, APRIL 2002 barium specimen which is called its type specimen, every genus name is tied to a type species name, and every family name is tied to a type genus name. If one wants to use the family name Scrophulariaceae for a particular group of genera, then the type genus Scro phularia (bee plants) needs to be one of the genera that is in the group. Simi- larly, if one wants to use the generic name Scro phularia for a particular group of species, then the type species Scro phularia no do sa must be included in that group of species. If one wants to use the name Sc ro phularia c alifo rnic a for a particular group of populations, then one needs to make sure that the type specimen of that name matches plants from those populations. Sometimes, the same entity (a species, genus, or family) has more than one published name. In that case, which name does one choose? Here, we turn once again to the ICBN which says that we must use the oldest published name beginning from 1753 (the publication date of Linnaeus’s Species Plantarum), Aceraceae ( Acer macrophyllum or big-leaf maple shown here) is now placed in the Sapindaceae, a mostly tropical family. Photograph by G. Webster. unless taxonomists vote to con- serve a later name. This is known seedling leaves). These classes were called cladistic trees, and based on as the principle of priority. each divided into a nested hierarchy the branching pattern of the trees, With the combination of of subclasses, orders, families, gen- “monophyletic” groups of related new molecular data, the wide era, and species. The groups at each species, genera, and families were use of cladistic analyses, strict level of the hierarchy were defined carved out (see sidebar on pages adherence to the rules of cladis- using all the evidence available at 4–7). tic classification, and the appli- the time. Even so, there were fami- One of the most thought- cation of the rules of the ICBN, lies, orders, or subclasses that were provoking articles was written by you can now see how we have known to be problematic (not clearly Mark Chase et al. (1993). In it, the arrived at a point in botanical defined), and it was certain that fur- authors produced cladistic trees history where the names of flow- ther work was needed to clarify their based on chloroplast gene data that ering plant groups are changing evolutionary relationships. called into question a number of drastically. We have come a long In the late 1980s, with the in- Cronquist’s subclasses and orders, way in our understanding of the creasing use of molecular data not to mention the validity of the evolution of the flowering plants, analyzed using cladistics, journal dicotyledons as a taxonomic group. and these changes are, we hope, articles pointing out the shortcom- As the 1990s continued and the use inching us toward a truly phylo- ings of previous classification sys- of DNA sequence data by plant genetic system of classification. tems began to appear. The authors scientists became widespread, ar- published branching diagrams ticles questioning the make-up of

VOLUME 30:2, APRIL 2002 FREMONTIA 7 also get reshuffled, but the genera own family, Ruppia is excluded from involved in the reshuffle are not Potamogetonaceae, Halesia is being commonly found in California. taken out of the Styracaceae, and Other Je p s o n M an u a l families Sambuc us and Viburnum are being will simply disappear in the new taken out of the Caprifoliaceae and classification system, “gobbled up” placed in the Adoxaceae. by closely-related families of which The bottom line is that change they are just a more specialized is coming, and if you think that you member. Hydrophyllaceae and are in trouble, just think what it will Lennoaceae are included in Boragi- be like trying to incorporate some of naceae; Empetraceae and Epacri- these changes into the filing system daceae are placed in Ericaceae; and at the UC Davis Herbarium! We Aceraceae and Hippocastanaceae are still trying to curate our collec- are being included in a mostly tropi- tions to agree with some of the name cal family that wasn’t even included changes in The Jepson Manua l(we in The Jepson Manua—l the Sapin- just finished changing Haplopappus daceae (which includes golden rain to Ericameria). However, we cannot tree). stick our heads in the sand, because In addition, the Chenopodiaceae some recent US guidebooks have are placed in Amaranthaceae, Ascle- already begun to incorporate the piadaceae in Apocynaceae, Lemna- proposed family name changes, and ceae in Araceae, Capparaceae in it looks like we may have to learn to Brassicaceae, Punicaceae in Lythra- accept that Triteleia laxa (Ithuriel’s ceae, Martyniaceae in Pedaliaceae, spear) is now in the Themidaceae Philadelphaceae in Hydrangeaceae (“What?” you say). (a family not included in The Jepson Of course, only time will tell Manual), and Cuscutaceae in Con- how much of the APG system will volvulaceae. The Malvaceae become really be accepted by the scientific the equivalent of the Cronquistian community, not to mention lay order Malvales, “inhaling” Ster- botanists, especially when our cur- Salicornia, pickleweed (top) and Salsola, culiaceae (the chocolate family, rent flora of California follows Russian thistle (bottom) of what was the which includes our flannelbush, Cronquist. But if these strange fam- Chenopodiaceae. Some genera in this Fremo nto dendro) nas well as the ily names begin to appear in Cali- family may end up in the Amaranthaceae. Photographs by L. Wheeler. mostly tropical families Tiliaceae fornia local floras, garden books, and Bombaceae (neither of which and articles, you can haul out this various plant families appeared. are in The Jepson Manua).l article and use Table 1 to translate This research culminated in the Some of the mergers mentioned into “Jepsonese.” publication of the APG paper in above are expected, because bound- 1998 and the textbook by Judd et al. aries between the families in ques- in 1999 (revised in 2002). tion have been muddy for some REFERENCES Although many plant families time. For instance, some teachers recognized in The Jepson Manual out there may breathe a sigh of re- Angiosperm Phylogeny Group. 1998. are changed to some degree in the lief at the combination of Cheno- An ordinal classification for the new classification system (Table 2 podiaceae and Amaranthaceae. In families of flowering plants. Annals is an attempt at a complete listing), other cases, the families that are o f the Misso uri Bo tanical Garden some families are affected more than disappearing consisted of only one 85:531–553. others. The Scrophulariaceae (and genus, and so the addition of that Chase, M., et al. 1993. Phylogenetics of seed plants: an analysis of nucle- closely related families such as genus to a closely-related family is otide sequences from the plastid Plantaginaceae, Orobanchaceae, really not that radical a change. gene rb cL. Annals o f the Missouri Callitrichaceae, and Hippuridaceae) The converse happens as well. Botanical Garde n80:528–580. and the Liliaceae are radically re- Some families are being narrowed, Cronquist, A. 1981. An Inte grate d Sy s - shuffled or broken down into dif- with an errant genus being removed tem of Classification of Flowering ferent subunits (see articles by and placed in a family of its own. Plants. Columbia University Press. Olmstead and Kelch in this issue). For example, Sparganium is taken New York, NY. The Lamiaceae and Verbenaceae out of Typhaceae and placed in its Hickman, J. 1993. The Jepson Manual,

8 FREMONTIA VOLUME 30:2, APRIL 2002 TABLE 2. PRELIMINARY SUMMARY OF FAMILIES IN THE JEPSON MANUAL AND THEIR NAME CHANGES ACCORDING TO THE APG * SYSTEM APG System (1998) Judd, et al. (2002) MONOCOTYLEDONS Alismataceae Aponogetonaceae Araceae Includes Lemnaceae, Same as APG. but excludes Acoraceae. Arecaceae Commelinaceae Cymodoceaceae Cyperaceae Hydrocharitaceae Iridaceae Juncaceae No change? Perhaps not monophyletic, but no change yet. Juncaginaceae Lemnaceae Included in Araceae. Same as APG. Liliaceae Narrowed to exclude many genera; Same as APG. see Kelch article on page 23. Orchidaceae Poaceae Pontederiaceae Potamogetonaceae Includes Zannichelliaceae, Excludes Ruppiaceae. but excludes Ruppiaceae. Scheuchzeriaceae Typhaceae Excludes Sparganiaceae. No change. Zannichelliaceae Included in Potamogetonaceae. No change. Zosteraceae

DICOTYLEDONS Acanthaceae Aceraceae Included in Sapindaceae. Same as APG. Aizoaceae Amaranthaceae Broadened. Includes all Chenopodiaceae Includes all Chenopodiaceae. except Sarcobataceae. Anacardiaceae Apiaceae Narrowed. Hydrocoty lande related Broadened. Includes all genera transferred to Araliaceae. Araliaceae. Apocynaceae Broadened. Includes Asclepiadaceae. Same as APG. Aquifoliaceae Araliaceae Broadened. Includes Hydrocoty lande Included in Apiaceae. related genera. Aristolochiaceae Asclepiadaceae Included in Apocynaceae. Same as APG. Asteraceae Balsaminaceae Basellaceae Bataceae *Angrosperm Phylogeny Group Berberidaceae

VOLUME 30:2, APRIL 2002 FREMONTIA 9 TABLE 2 , continued APG System (1998) Judd, et al. (2002) Betulaceae Bignoniaceae Boraginaceae Broadened. Includes Hydrophyllaceae Includes Hydrophyllaceae except and Lennoaceae. for Hydroleaceae; mentions that Lennoaceae may also be part of Boraginaceae. Brassicaceae Broadened. Includes Capparaceae. Same as APG. Buddlejaceae Burseraceae Cabombaceae Included in Nympheaceae. Same as APG. Cactaceae Callitrichaceae Included in Plantaginaceae; see article by Same as APG. Olmstead (this issue on page 13). Calycanthaceae Campanulaceae Cannabaceae Capparaceae Included in Brassicaceae. Same as APG. Caprifoliaceae Excludes Sambucus and Viburnum (which are Excludes Sambucus and Viburnum included in the Adoxaceae); excludes (Adoxaceae) but includes Linnaeaceae. Dipsacaceae and Valerianaceae. Caryophyllaceae Celastraceae Broadened to include Hippocrateaceae. Same as APG. Ceratophyllaceae Chenopodiaceae Included in Amaranthaceae, with the Included in Amaranthaceae. exception of Sarcobataceae. Cistaceae Convolvulaceae Broadened to include Cuscutaceae and Same as APG. Dichondraceae. Cornaceae Broadened to include other non-California Same as APG. genera. Crassulaceae Crossosomataceae Cucurbitaceae Cuscutaceae Included in Convolvulaceae. Same as APG. Datiscaceae Dipsacaceae No change. Included in Caprifoliaceae. Droseraceae Eleagnaceae Elatinaceae Empetraceae Included in Ericaceae. Same as APG. Ericaceae Broadened; includes Empetraceae and other Same as APG. non-California genera. Euphorbiaceae Fabaceae Fagaceae Fouquieriaceae Frankeniaceae Garryaceae Gentianaceae Geraniaceae

10 FREMONTIA VOLUME 30:2, APRIL 2002 TABLE 2 , continued APG System (1998) Judd, et al. (2002) Grossulariaceae Gunneraceae Haloragaceae Hippocastanaceae Included in Sapindaceae. Same as APG. Hippuridaceae Included in Plantaginaceae; see article by Olmstead (this issue on page 13). Same as APG. Hydrophyllaceae Included in Boraginaceae. Same as APG. Hypericaceae Included in Clusiaceae. Same as APG. Juglandaceae Koeberliniaceae Krameriaceae Lamiaceae Broadened to include many Verbenaceae. Same as APG. Lauraceae Lennoaceae Included in Boraginaceae. Mentioned as perhaps belonging in Boraginaceae. Lentibulariaceae Limnanthaceae Linaceae Loasaceae Lythraceae Broadened; includes Punicaceae, Same as APG. Sonneratiaceae, and Trapaceae. Malvaceae Broadened, includes Sterculiaceae, Tiliaceae, Same as APG. and Bombacaceae. Martyniaceae Included in Pedaliaceae. Same as APG. Meliaceae Menyanthaceae Molluginaceae Moraceae Myoporaceae Myricaceae Myrtaceae Nyctaginaceae Nymphaeaceae Broadened. Includes Cabombaceae. Same as APG. Oleaceae Onagraceae Orobanchaceae Broadened to include root parasites of the Same as APG. Scrophulariaceae; see article by Olmstead (this issue on page 13). Oxalidaceae Paeoniaceae Papaveraceae Philadelphaceae Included in Hydrangeaceae. Same as APG. Phytolaccaceae Pittosporaceae Plantaginaceae Broadened to include genera of traditional Same as APG. Scrophulariaceae; see article by Olmstead (this issue on page 13). Platanaceae Plumbaginaceae Polemoniaceae

VOLUME 30:2, APRIL 2002 FREMONTIA 11 TABLE 2 , continued APG System (1998) Judd, et al. (2002) Polygalaceae Polygonaceae Portulacaceae No change? Discusses the possibility that the family is not monophyletic. Primulaceae Punicaceae Included in Lythraceae. Same as APG. Rafflesiaceae Ranunculaceae Resedaceae Rhamnaceae Rosaceae Rubiaceae Rutaceae Salicaceae Santalaceae No change? Discusses the possibility that the family is not monophyletic. Sarraceniaceae Saururaceae Saxifragaceae Scrophulariaceae Narrowed; see article by Olmstead Same as APG. (this issue on page 13). Simaroubaceae Narrowed to exclude genera not found in Narrowed to exclude genera not California. found in California. Simmondsiaceae Solanaceae Staphyleaceae Sterculiaceae Included in Malvaceae. Same as APG. Styracaceae Narrowed. Excludes Halesiaceae. Same as APG? Tamaricaceae Thymelaeaceae Tropaeolaceae Ulmaceae Narrowed. Excludes Celtidaceae. Same as APG. Urticaceae Valerianaceae No change. Included in Caprifoliaceae. Verbenaceae Narrowed; excludes many genera now placed Same as APG. in the Lamiaceae; also excludes Avicenniaceae. Violaceae Viscaceae Included in Santalaceae. No change. Vitaceae Zygophyllaceae Circumscription changed. A few genera placed in the Peganaceae.

Higher Plants o f Califo rn.i aUniver- Skinner, M. and B. Ertter. 1993. genetic classification of flowering sity of California Press. Berkeley, Wither rare plants in The Jepson plants. Aliso 13:365–389. CA. Manual? Fremontia 22:23–27. Judd, W., C. Campbell, T. Kellogg, and Takhtajan, A. 1997. Diversity and Clas- P. Stevens. 2002. Plant Systematic s: sification of Flowering Plan tCos. lum- Ellen Dean, Plant Bio lo gy, One Shields A Phylogenetic Approa.Schinauer As- bia University Press. New York, NY. Ave, University of California, Davis, CA sociates, Inc. Sunderland, MA. Thorne, R. 1992. An updated phylo- 95616. [email protected]

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