Mauseth JD, Landrum JV. Relictual vegetative anatomical characters in Cactaceae: the genusPereskia.
JOURNAL OF PLANT RESEARCH 1997;
110:55-64. [PMID:
27520044 DOI:
10.1007/bf02506843]
[Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/1996] [Accepted: 01/11/1997] [Indexed: 06/06/2023]
Abstract
The genusPereskia, which contains numerous morphological features considered relictual in the Cactaceae, has numerous anatomical features that we consider to be relictual also. These were studied to establish a basis for determining the ways that morphogenic mechanisms and anatomical characters diversified as the family evolved. ThesePereskia features may be relictual in the family: epidermis predominantly unistratose and lacking crystals; hypodermis absent or of about three layers of weakly collenchymatous cells with druses; cortex thin and predominantly parenchyma with druses and mucilage cells but lacking cortical bundles; secondary phloem without early differentiation of sclerenchyma but with secondary sclereids developing later, either idioblastically or in clusters; ergastic substances lacking from old secondary phloem; wood with a matrix of libriform fibers (mostly septate and nucleate), scanty paratracheal parenchyma, vessels solitary or in small clusters, perforations simple, pitting circular, oval or very broad; wide-band tracheids absent; ray cells slightly thick-walled, lignified, upright, isodiametric or procumbent; all primary rays narrow; pith without medullary bundles; leaves lacking hypodermis, with only weak development of palisade mesophyll; veins of four orders, strongly distinct in size, none with fibers; vessels in leaves narrower than those in stems.
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