摘要:

The nodal anatomy ofXanthophyllumis unilacunar with a single broad trace departing the cauline stele. The “stipular glands” or extra floral nectaries of some species are vascularized by bundles originating from the base of the leaf trace. Considerable variation exists among species in petiole vasculature with siphonosteles, steles with medullary bundles and simple, flat traces present. The lamina also shows variation in the presence or absence of a hypodermis, nature of vein sheathing, presence or absence of abaxial epidermal papillae, amount of intercellular spaces, and mature stomatal patterns which range from anisocytic and paracytic to those in which no subsidiary cells are discernible. Of nearly uniform occurrence throughout the genus are extraordinary tracheoid foliar idioblasts, which are confined to the veins in terminal or subterminal positions. The large amount of variation in leaf anatomy is shown to be taxonomically significant within the ge

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1973.tb01732.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

Anticipating a complete revision of the genusXanthophyllum, which will be printed inBlumeawithin two years, one new subgenus, 17 new species, one new subspecies and two new varieties are described, and for three names a new status is proposed. This is done for nomenclatural reasons, validating the new names in W. C. Dickison's study of the leaf anatomy ofXanthophyllum, published elsewhere in this Journal.

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1973.tb01733.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

Of three computer‐generated classifications ofPyrusspecies, produced respectively from 29 chemical characters, 22 botanical characters and all 51 characters taken together, the classification based upon both chemical and botanical characters agrees best with the known geographical distributions of the species. Where either chemical or botanical characters are separately employed, the classifications contain seriously misplaced species. The numerical classification based upon all 51 characters lends some support to the division of the genus into four principal groups of species: the East Asian pea pears, the larger‐fruited East Asian pears, the North African pears and the European and West Asian pears.P. longipes, P. betulifoliaandP. cordataare considered as being connecting links between the East Asian pea pears, the larger‐fruited East Asian pears and the European and West Asian pears. Some speculations are made on the phylogenetic relationships amongPyrussp

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1973.tb01734.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

The pistil ofAndrocymbiumclosely resembles that ofColchicum: it is tricarpellate usually, syncarpous and multiovulate, and the carpels of most species have open sutures and bitegmic ovules. The only species with closed carpellary sutures,A. dregeihas monotegmic ovules. There are always three dorsal bundles and three compound septal bundles, which latter may bifurcate into simple septal bundles. Six placental bundles (two per carpel) are differentiated, either separately from the compound septal bundles or as lateral branches of them. A statistical evaluation of 47 species (6 genera) of the hemisyncarpous Wurmbaeoideae shows a significant tendency for bitegmic ovules and two simple septal bundles per septum to be associated with open sutures and for monotegmic ovules and no septal bundles to be associated with closed sutures.

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1973.tb01735.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

Comparative ontogenetic studies were made of the gametophyte generation grown from spores taken from natural populations of the four species ofSadleria.Significant differences were found between species in the nature of the perispore, presence or absence of a terminal trichome on the one‐dimensional filament, and the sequence of gametangia formation. Breeding tests were also conducted and sporophytes screened for recessive lethals. Three species were found to have intergametophytic mating systems and heterozygosity for sporophytic lethals. Of these,S. cyatheoidesandS. souleyetianahave retained the capability for monogametophytic reproduction, whereasS. pallidahas not. The fourth species,S. squarrosa, has a prolonged gametophyte generation intolerant of higher light intensities. Correlations between frequency in nature, habitat diversity, ability to colonize newly formed lava flows, reproductive biology and syndromes of the gametophyte generation are mad

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1973.tb01736.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

A fine‐structural survey of three species ofProrocentrumand five species ofExuviaellahas shown that there is no basic distinction between the two genera. An earlier proposal that the genusExuviaellabe abandoned and its species incorporated intoProrocentrumis supported by this work. The basic fine structure of the species studied is typical of the dinoflagellates but there are adequate distinctive features to justify the retention of the separate order Prorocentrales. Within the order some ultrastructural differences noted between species are types of pyrenoid, ornamentation and structure of the thecal plates and presence or absence of trichocysts and fibrillar bodie

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1973.tb01737.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY