Aliso: A Journal of Systematic and Floristic Botany Aliso: A Journal of Systematic and Floristic Botany

The xeromorphic Mexican spiraeas (S. hartwegiana and S. northcrajii1) are shown by cladistic and phenetic analysis to be more closely allied to Petrophytum, Kelseya, and Luetkea than to the more mesophytic Spiraea. Within Spiraea the Mexican spiraeas appear more closely related to the Old World subgenus Metaspiraea. The xeromorphic Mexican spiraeas, as well as Petrophytum, Kelseya and Luetkea, are considered to be New World derivitives of Old World Spiraea subgenus Metaspiraea that have become part of the Madro-Tertiary Geoflora, with each genus achieving some level of xeromorphic adaptation. The Mexican spiraeas are thus considered generically distinct and are placed in a new genus Xerospiraea containing one species X. hartwegiana. The more northern Spiraea north craflii is placed in synonomy under X. hartwegiana.


INTRODUCTION
Studies of Polemoniaceae for the Chihuahuan Desert Region Flora have revealed two new taxa of Ipomopsis from northern Coahuila that are described herein.In addition, Ipomopsis pringlei from the Sierra Madre Occidental of northem Mexico, is distinguished from the more northern l.macombii, and an anomalous new record for the genus is reported for California.TAXONOMY Ipomopsis wendtii Henrickson sp.nov.
The new species is very distinct from other Ipomopsis and can be distinguished by several characters including the large calyx in relation to the corolla size, the short, included style and included stamens, the disposition of flowers, solitary at mid-stem nodes, and somewhat aggregated on lateral branches.Within Ipomopsis, as recognized by Grant (1956), I. wendtii seems to fit best within section Ipomopsis which consists of erect, few-branched, rosulate perennials mostly with regular, long-tubed corollas with exserted or included styles.In other characters I. wendtii is very similar to I. pin nata (Cav.)V. Grant of section Phloganthea (Gray) V. Grant, having slightly zygomorphic corolla lobes and deeply included styles.
Type. -MEXICO.COAHUILA: Infrequent perennial on north, igenous slope of Picacho del Centinela, Del Carmen Mts., 6000 ft, 24 Aug. 1954, B.  The new taxon is distinguished on the basis of a rather delicate, herbaceous habit, lax inflorescences with mostly solitary flowers on long pedicels, distinctive, long calyx lobes, orange-red corollas with ovate, shortly apiculate lobes and a series of five well developed invaginations at the base of the broad corolla tubes at the point where the corolla traces divide from 1 to 3 traces along the midpetaline line, 2.5-4 mm above the corolla tube base (Fig. 2a, b).The new taxon is most similar to I. aggregata subsp.jormosissima in disposition of its anthers, a character much emphasized by Grant and Wilken (1986) in their recent treatment of the Ipomopsis aggregata complex, and they would perhaps consider this rather restricted taxon to be a minor taxon within the species complex.However, while I have seen specimens from throughout the range of /. aggregata with one or another of these characters, the combination of characters represented in these collections stands in strong contrast with other collections of I. aggregata subsp.jormosissima (heretofore known as =1.a. var.texana; see Wilken and Allard [1986]) in the Sierra Madera del Carmen.Ipomopsis aggregata subsp.jormosissima is taller, more woody-stemmed, with flowers usually more aggregated in thyrses along upper stems, with calyx lobes shorter than to only slightly longer than calyx tubes (Fig. 2f-g) (3-4 mm long according to Grant and Wilken [1986]), with deeper red corollas with narrower, more elliptical-Ianceolate, longer attenuate corolla lobes (Fig. 2e) that are more flaring and typically with reddish flecks on the inner surface, and the distinct invaginations near the relatively narrow corolla tube base are much more poorly developed at least in local populations.
Some characters present in the new subspecies occur in populations otherwise attributable to l. aggregata subsp.jormosissima.In the Sierra Madre Oriental near Galeana, Nuevo Leon, Mexico, some collections show tendencies to have some solitary flowers on long pedicels and calyces with lobes longer than tubes Within the Sierra Maderas del Carmen these taxa appear somewhat ecologically separated.Ipomopsis aggregata subsp.carmenensis is apparently restricted to the upland rhyolite pine-oak-basswood woodlands and forest from 1800 to 2400 m while l.aggregata subsp.jormosissima is more wide ranging occurring from lower chaparral-like scrub up to pine-oak woodlands from 1300 to 2000 m in both limestone and rhyolite areas.
/pomopsis macombii occurs in Pima, Pinal, Santa Cruz, and Cochise counties in southeastern Arizona, Hidalgo, Luna counties in southwestern New Mexico, south into northeastern Sonora, western and extreme eastern Chihuahua, extreme west central Coahuila and in central Nuevo Leon near Galeana (where corollas are generally smaller and nearly white in color).In 1943 I. M. Johnston described as new Gilia calothrysa from extreme eastern Coahuila and adjacent Chihuahua.However, G. calothrysa fits well into I. macombii having corolla tubes about 13 mm long, reflexed corolla lobes 5.5 mm long, 4 mm wide, calyces 6-6.5 mm long and styles 11 mm long.It differs only in-having the lowermost stamen filaments 1.2-1.7 mm long, much longer than in typical /. macombii (0.7-1 mm); in this character it approaches / .pringlei.But I do not deem this difference sufficient to recognize the taxon as distinct from I. macombii particularly when G. calothrysa is known from so few collections.
/POMOPSIS EFFUSA NEW TO CALIFORNIA AND THE UNITED STATES /pomopsis effusa (Gray) Moran [Loeselia effusa Gray, Gilia effusa (Gray) Macbride] has been considered endemic to the Sierra Juarez and the Sierra San Pedro Martir in northern Baja California (Wiggins 1980) where it is recorded from chaparral, gravelly flats (often with Pinus quadrifolia) and in montane meadows (with Pinus jeffreyi) from 875 to 2600 m (Moran 1977).Moran notes at its lower elevations it occurs scattered along streambeds.While compiling a floristic check-list for a proposed transmission line right-of-way in southeastern Imperial County, California, I found two plants of Ipomopsis effusa (Henrickson 19590) growing at the terminus of Pinto Wash.The site is located just north of highway 93, about 3 miles north of the United States-Mexico border at sea level and consists of the open sandy fan where Pinto Wash terminates and the water soaks into the sandy substrate.The site occurs in a Larrea scrub community and common associates in the fan include Psorothamnus spinosus, Encelia !rutescens, and Hymenoc/ea salsola.The wash has its origin in the upper elevations of the Sierra Juarez in Baja California and it is apparent that the seeds were washed down in floodwater early that spring as the margins of the streambed were littered with small pine cones presumably of Pinus quadrifolia.This represents the first record of this annual species in California and the United States (for a description of the plant see Moran [1977]).The plants appeared vigorous at the time of collection.The plants presumedly would have successfully set seed in this locality.Repeated introductions would be expected whenever the stream flows.Vouchers are at CAL, RSA.

Table I .
Comparison of selected quantitative characteristics of I. macombii and I. pringlei.