Lathrop and Thorne published their final summary of the Flora of the Santa Rosa Plateau in 1985 as Southern California Botanists Special Publication No. 1. This webpage gives the changes made to update that Flora to the names used in the Jepson Manual.
The Number of Taxa In Lathrop and Thorne (1985)
In order to make sure no taxa are inadvertently omitted in the updated list, I need to establish how many taxa are in their list, which, surprisingly, is by no means obvious.
They have a summary table which lists a total of 588 "species". (The word species is in quotes because their accounting for "species" includes counting each of the two subspecies of Lotus scoparius - see below.) Here is their exact summary table as published:
Indigenous Naturalized Families Genera Species Additional
Pteridophytes 10 16 20 0 0 0 Conifers 1 1 1 0 0 0 Dicotyledons 67 210 357 1 43 81 Monocotyledons 16 45 91 0 16 38 Totals 94 272 469 1 59 119 Grand Totals: Families 95; Genera 331; Species 588
Their table has four errors in it. For the dicots, the number of indigenous families is actually 66 and the number of additional naturalized families is actually 2 (they failed to indicate that Geraniaceae was made of entirely non-native taxa). For the naturalized monocots, the number of species is 39, not 38 (see below), making the total "species" 589.
Here are the corrections to their number of 588 "species" to arrive at my total of 583 Jepsonized taxa actually present in their flora:
- First, their total should actually have been 589 taxa, since they miscounted the naturalized monocots by one. This was an easy mistake to make prior to computerized lists. They reported 38 naturalized monocots, but their flora lists 39 separate entries. I verified every other number in their table; in every case, the number corresponded to the number of separate entries, delineated by a taxon name on an unindented line. So there is no ambiguity in how they counted "species" in their table; they simply miscounted one of their eight separate taxa totals (four categories separated into natives and naturalized taxa).
- Second, I need to make clear how they counted "species". Lathrop and Thorne have an interesting attitude toward varieties:Subspecific names are used where appropriate, but varieties, considered here as minor genetic variants with little if any geographic or ecological significance, are placed in parentheses or brackets when mentioned at all.
Consistent with this attitude, Lathrop and Thorne do give subspecies names for a significant fraction of the flora. Species with two varieties are never accorded separate entries, but instead the varieties are simply mentioned or discussed within the species entry.
However, Lathrop and Thorne are inconsistent in counting species on their list that have two observed subspecies. They give separate entries to the two subspecies of Lotus scoparius, but combine the two subspecies of Nemophila menziesii into one entry. Thus their taxa count should be increased by one from the two subspecies of Nemophila menziesii. (For their table, they counted each separate entry in their annotated list.)
Furthermore, Lathrop and Thorne treated Eleocharis radicans (Poir.) Kunth as the same species as Eleocharis acicularis (L.) R. & S., probably because a synonym for E. radicans is Eleocharis acicularis var. radicans Britton. They apparently observed both taxa, since they state "Eleocharis acicularis [incl. E. radicans]". These remain separate species in the Jepson Manual, so their taxa count again needs to be increased by one.
Omissions in previous versions of the updated Lathrop and Thorne list are often due to this subtle way of mentioning that they had found two taxa, but which they consider as one species, through the word incl. inside brackets.
Finally, since the Jepson Manual lists the following variety names, these single taxa of Lathrop and Thorne have now become two taxa:
- Castilleja densiflorus var. densiflorus and var. gracilis. Again, this is easy to miss in their flora, since the way they indicate two varieties, when one variety has the species name repeated as the variety name, is "Orthocarpus densiflorus [incl. var. gracilis]". When they find only a single variety, they state it this way: "Agrostis stolonifera var. major" or "Calandrinia ciliata [var. menziesii]", depending on the significance they attribute to each variety name.
- Quercus agrifolia var. agrifolia and var. oxyadenia, from "Quercus agrifolia [incl. var. oxyadenia]".
- Vulpia myuros var. hirsuta, said to be a very abundant annual of dry open places in grassland, and var. myuros, said to be infrequent in grassland and grassy openings in chaparral, and locally abundant in the vernally moist zone of vernal pools. Here they must have considered the varieties as a bit more taxonomically worthy, since they must have distinguished them morphologically and ecologically.
So the net taxa count is increased by five, from 589 to 594, from the two taxa contained within five species (Nemophila, Eleocharis, Castilleja, Quercus, and Vulpia genera.)
- Third, Lathrop and Thorne included 12 taxa which they did not observe, but which "could be expected to occur on the Santa Rosa Plateau, but were not found". Although these taxa are denoted with a question mark preceding their names, they were included in the summary table of the flora.
Corresponding with the usual custom of including only taxa actually observed in floras, those taxa are not included here, subtracting 12 taxa from their published list. The net taxa count is now 594 - 12 = 582.
- Fourth, Lathrop and Thorne omitted Cotula coronopifolia, which they listed in their 1983 Flora of the Vernal Pools on the Santa Rosa Plateau, published in Aliso 10: 449-469. This makes a grand total of 583 taxa published by Lathrop and Thorne.
Change In The Number of Taxa In Lathrop and Thorne (1985) From Update To The Jepson Manual Names
The Jepsonized Lathrop and Thorne list has four fewer taxa due to the Jepson Manual combining species that were separate in Lathrop and Thorne:
- Two taxa, Mimulus puniceus and M. puniceus X M. aurantiacus, were lost when M. puniceus was merged with M. aurantiacus;
- One taxon was lost when Callitriche longipedunculata and C. marginata were merged;
- One taxon was lost when Lupinus agardianus was merged with L. concinnus.
Thus the final Jepsonized count is 583 - 4 = 579.
It is amusing that some of the varieties scorned as being of doubtful significance by Lathrop and Thorne, such as the two varieties of Castilleja densiflorus, have become subspecies or, in other case, even separate species in the Jepson Manual. Yet in four cases, two species that were separate in Lathrop and Thorne became merged into a single species in the Jepson Manual, no longer even accorded varietal status. This, of course, only points out how difficult it is in some cases for botanists to agree on the boundaries of a species or subspecies; it would not be surprising if a future flora restored the positions taken by Lathrop and Thorne.
The revised Jepsonized and corrected Lathrop and Thorne table, using only the taxa they actually observed, is:
Indigenous Naturalized Families Genera Species Taxa Additional
Taxa Pteridophytes 11 16 20 20 0 0 0 0 Conifers 1 1 1 1 0 0 0 0 Dicotyledons 67 210 348 354 2 41 74 74 Monocotyledons 12 46 92 92 0 17 36 38 Totals 91 273 461 467 2 58 110 112 Grand Totals: Families 93; Genera 331; Species 571; Taxa 579
The number of families and genera changed both from the different Jepson Manual treatment of families and from changing some genera names.
Copyright © 2003-2005 by Tom Chester.
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Comments and feedback: Tom Chester
Updated 10 January 2005.