Update Of
The Lathrop and Thorne (1985) Flora Of The Santa Rosa Plateau
To The Jepson Manual Names

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
FamiliesGeneraSpecies Additional
Pteridophytes101620 000
Conifers111 000
Dicotyledons67210357 14381
Monocotyledons164591 01638
Totals94272469 159119

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:

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:

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
FamiliesGeneraSpeciesTaxa Additional
Pteridophytes11162020 0000
Conifers1111 0000
Dicotyledons67210348354 2417474
Monocotyledons12469292 0173638
Totals91273461467 258110112

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.

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Copyright © 2003-2005 by Tom Chester.
Permission is freely granted to reproduce any or all of this page as long as credit is given to me at this source:
Comments and feedback: Tom Chester
Updated 10 January 2005.