Flora of North America species comparison

Judgments have varied regarding the rank Garrya lindheimeri, as illustrated by the synonymy above. Evidence counter to uniting it with Garrya ovata includes their ecological distinction and allopatry over most of their ranges. Morphological differences between G. lindheimeri and G. ovata are at least comparable to those among some of the California species, which intergrade to a greater extent than these do.

Garrya lindheimeri and G. goldmanii are allopatric in Texas, with the former restricted to the Edwards Plateau and adjacent Lampasas Cut Plain and the latter found only in trans-Pecos Texas. They become sympatric in Coahuila, Mexico, and remain distinct although hybrids and perhaps introgressants may be formed. Garrya goldmanii occurs in more xeric habitats, as indicated by the differences in distribution and ecology in Texas, and the ecological distinction also apparently exists in Coahuila. Their distinction where sympatric implies a degree of reproductive isolation and provides rationale for maintaining both at specific rank.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Species 17 (8 in the flora).

Two sections of Garrya have been recognized (see key below). Species of sect. Garrya range from Washington to Baja California and New Mexico, with one outlier in Guatemala, G. corvorum Standley & Steyermark. Section Fadyenia de Candolle ranges from trans-Pecos Texas to Arizona and from Mexico (including Baja California) to Central America plus the West Indies (Cuba, Hispaniola, and Jamaica). In addition to the features noted in the key, in sect. Garrya pistillate flowers bear a pair of small appendages at the ovary apex near the style base, whereas in sect. Fadyenia pistillate flowers occasionally produce two foliaceous bracts partially adnate to the ovary. The phylogenetic distinction between the two sections has been confirmed by D. O. Burge (2011).

The staminate flowers in pendulous aments of Garrya are similar to those in other genera specialized for wind-pollination. The staminate aments are more flexible than the pistillate and more responsive to wind currents. P. A. Munz (1959) noted that in California many of the species intergrade extensively where their distributions overlap, and hybridization and intraspecific variation underlie continuing uncertainty about delimitations of taxa. Natural hybrids, however, have not been reported elsewhere. The artificial hybrids G. ×issaquahensis Talbot de Malahide ex E. C. Nelson (G. elliptica × G. fremontii) and G. ×thuretii Carrière (G. elliptica × G. fadyenii Hooker) have been bred for garden planting.

The common name silktassel alludes to the sericeous vestiture of the long, showy aments in sect. Garrya. Plants are cultivated mainly for the foliage and showy staminate aments, and cultivars are mostly staminate plants propagated from cuttings.

Stem extracts of Garrya laurifolia Bentham are toxic but are used as an antidiarrhetic throughout rural Mexico, and bark extracts were reportedly used by Native Americans to treat fever (G. V. Dahling 1978).

(Discussion copyrighted by Flora of North America; reprinted with permission.)