Wood Anatomy of Fouquieriaceae in Relation to Habit, Ecology, and Systematics; Nature of Meristems in Wood and Bark

Abstract

Qualitative and quantitative data are presented for wood of all species of Fouquieriaceae, the samples selected so as to cover important variables with respect to organography and age . Wood contains fibertracheids (plus a few vasicentric tracheids) . Diffuse axial parenchyma is mostly grouped as diffusein-aggregates or diffuse clusters (new term), with transitions to pervasive axial parenchyma in some species. Rays are Heterogeneous Type II. These wood features are relatively unspecialized and are consistent with placement of the family in Ericales s.1. as defined in recent DNA-based cladograms. Xeromorphic wood in nonsucculent species occurs only in Fouquieria shrevei; the lateral branches of F. columnaris also have xeromorphic wood . If the preceding two instances and proliferated parenchyma of Lhe three succulent species (F. columnaris, F. fasciculata, and F. purpusii) are excluded from quantitative studies, wood of Fouquieriaceae is rather mesomorphic, despite Lhe habitats occupied by the family. This paradox is explained by the very sensitive drought deciduousness. Also, the succulent species produce water-storage parenchyma by means of expansion of rays and axial parenchyma bands. Details of these two types of meristems, as well as three other types of meristems within wood (not including vascular cambium) and four bark meristems (other than phellogen) are described; five of these merisrerns are newly reported for the family. Wood data permit recognition of both the three succulent and eight nonsucculent species within a single genus, in agreement with Henrickson (1972), but few wood features offer species characters. Most wood features, including the abundant reaction wood, are closely related to habit, organography. and ecology.

Branch length mediates flower production and inflorescence architecture of Fouquieria splendens (ocotillo)

“…One hallmark of branch autonomy is that individual branches accumulate and regulate water, carbohydrates, and nutrients (Sprugel et al 1991). Branches of F. splendens store sugars, starches, and oils in axial and ray parenchyma (Scott 1932;Nedoff et al 1985;Carlquist 2001), and they also have an anastomosing, continuous network of water-storage cells in the cortex (Scott 1932;Henrickson 1969;Carlquist 2001). These stored resources can presumably be mobilized for local use.…”

The role of wood anatomy in phylogeny reconstruction of Ericales

“…4 state 7; Dickison and Phend, 1985), while narrow vessels are present in shrubs to small trees of Acanthogilia , Cantua , Clavija, Fouquieria and Lysimachia (members of clades I–III; char. 4 states 0–1; Carlquist et al., 1984; Carlquist, 2001b; Lens et al., 2005a). The effect of secondary woodiness on the evolution of wood characters in Ericales has already been discussed in previous paragraphs.…”

Functional morphology of a sarcocaulescent desert scrub in the bay of La Paz, Baja California Sur, Mexico

“…Although present in other Mexican deserts, plants with fleshy, gigantic stems seem to be the identifying mark of the peninsula of Baja California. Sarcocaulescent trees possess morphological traits of both woody desert plants and cacti: They have true deciduous leaves and their external morphology resembles that of a tree, but the presence of chlorenchyma in their stem surface, the large amounts of radial and axial parenchyma in their trunks, and their capacity to store water and nutrients resembles in many aspects the morphology of cacti (Humphrey, 1935;Bullock, 1936;McVaugh and Rzedowski, 1965;Rzedowski and Kruse, 1979;Wiggins, 1980;Carlquist, 2001). Moreover, while the origin of cacti is monophyletic, sarcocaulescent plants belong to different, non-related families such as Anacardiaceae (genera Cyrtocarpa and Pachychormus), Burseraceae (Bursera), Euphorbiaceae (Jatropha and Pedilanthus), and Fouquieriaceae (Fouquieria).…”