Plants of Southern California: Ceanothus crassifolius, C. cuneatus, C. pauciflorus, and C. perplexans


This is a page currently being worked on. It is online now solely to present the photographs of the four species in Figs. 1 and 2.


Table of Contents


Photographs of the leaves of these four species
Photographs of the twigs of these four species
Introduction
Geographic Distribution of These Taxa
Photographs


Photographs of the leaves of these four species

C. crassifolius C. cuneatus C. pauciflorus C. perplexans
Fig. 1. The leaves of four Ceanothus species, labeled in the middle row. Top: The upper leaf surfaces. Bottom: The lower leaf surfaces.

C. crassifolius is easily distinguished by its hoary-white lower leaf surface, and broadly-turned-down edges with teeth.

C. perplexans is easily distinguished by it having more than 5 teeth, with a cupped upward leaf, and its different color.

C. cuneatus and C. pauciflorus are more subtly distinguished by whether the hairs on the underside of the leaf are straight or curly (and on how dense the hairs are on the twigs). Both of those species also have quite variable leaf shapes; only one of their leaf shapes is shown in this figure. Both species can also have ± round leaves.

Photos of C. crassifolius and C. pauciflorus by the author. Photos of C. cuneatus from an iNat observation by @dlbowls, verified by Dieter Wilken. Photos of C. perplexans from an inat observation by Alex Bairstow.

Click on the pictures for larger versions, which will be at iNat for those observations.

 


Photographs of the twigs of these four species


C. crassifolius

C. cuneatus

C. pauciflorus

C. perplexans
Fig. 2. The young twigs of four Ceanothus species, labeled below each picture..

Photos of C. crassifolius and C. pauciflorus by the author. Photos of C. cuneatus from an iNat observation by Luke Armstrong, verified by Dieter Wilken. Photos of C. perplexans from an inat observation by Alex Bairstow.

Click on the pictures for larger versions, which will be at iNat for those observations.

Introduction

There are nine Ceanothus taxa in southern California that have warty stipules and opposite leaves and branches. Three of those taxa are narrow endemics, found only in small areas, and two of those taxa are only found in the western Tranverse Range in southern California. That leaves just four species in play for most of southern California: Ceanothus crassifolius, C. cuneatus, C. pauciflorus, and C. perplexans.

The names for the first two species have remained stable with time, but the names for the last two species have changed several times in the last two decades. C. pauciflorus = C. greggii var. vestitus = C. vestitus var. vestitus, and C. perplexans = C. greggii var. perplexans = C. vestitus var. perplexans. The names used here are from the latest Jepson eflora treatment for Ceanothus from 2020 by Dylan O. Burge and Dieter H. Wilken.

The motivation for this page was when my understanding of C. cuneatus and C. pauciflorus was turned completely upside down in March 2021!

I had thought the C. cuneatus plants in the Warner Springs area of San Diego County, and in the San Jacinto Mountains area of Riverside County, were all good C. cuneatus, since they had mostly-flat leaves and they had the leaf variation shown in its JM illustration.

I also thought that C. pauciflorus, under the name of C. greggii vestitus, was confined to the desert edge of the TR, and not present in the PR.

Both of those concepts are what was reported in the floras when I learned these plants, including Munz, Beauchamp, and the first edition of the Jepson Manual.

Dieter Wilken took over the second edition Jepson Manual treatment, and made a change I didn't notice, placing C. greggii vestitus, under the name of C. vestitus, in the PR. Furthermore, he provided an entirely different key to distinguish C. vestitus from C. cuneatus.

I used that key on two separate all day field trips studying the plants I had thought were C. cuneatus in the Warner Springs area and at San Jacinto Mountain. To my surprise, they all turned out to be C. pauciflorus! So even thought the name of C. cuneatus has remained stable, the plants in that area have undergone a name change.

Page Not Yet Worked On Below This Point!

straightish appressed hairs:
https://www.inaturalist.org/observations/36516924

    Ceanothus crassifolius var. crassifolius
    Ceanothus crassifolius var. planus WTR and north
    Ceanothus cuneatus var. cuneatus
    Ceanothus cuneatus var. ramulosus  w TR and north
    Ceanothus megacarpus var. insularis  ChI
    Ceanothus ophiochilus Vail Lake
    Ceanothus otayensis Otay Mtn, San Miguel Mtns, Miramar
    Ceanothus perplexans
    Ceanothus vestitus

Note the hoary white lower surface for C. crassifolius; the glabrous upper leaf surface for C. cuneatus There is a progression from the leaf edges being broadly rolled down for C. crassifolius and slightly rolled down for C. cuneatus; to the entire leaf being slightly cupped upward for C. pauciflorus (not visible in these photographs) and markedly cupped upward for C. perplexans.

Geographic Distribution of These Taxa

Fig. 2. Geographic distribution of . Click on the maps for larger versions.

Photographs


Voucher data provided by the participants of the Consortium of California Herbaria.


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Copyright © 2021 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:
http://tchester.org/plants/analysis/ceanothus/crassifolius_cuneatus_pauciflorus_perplexans.html
Comments and feedback: Tom Chester
Last update: 5 April 2021