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An annotated list of vascular plants in Westland National Park and its vicinity includes about 620 native species, 22 varieties, 26 hybrids, and 114 adventive species. Ecological information is included and records are supported by herbarium specimens.

Summary Hybrids between the endemic Disphyma australe and two adventive species of Carpobrotus, namely C. edulis and C. aequilaterus, occur naturally in coastal areas throughout New Zealand. The hybrids are highly sterile triploids. Both exhibit parental characters although in size and form they resemble Disphyma more closely.

Summary Eight American cudweeds belonging to Gnaphalium section Gamochaeta are adventive to New Zealand. They are G. calviceps Fern., G. subfalcatum Cabr., G. pensylvanicum Willd., G. simplicicaule Willd. ex Spreng., G. purpureum Linn., G. ustulatum Nutt., G. spicatum Lam., and G. americanum Mill. Keys to cudweed groups and Gnaphalium sections, as well as to these adventive species, are provided together with species descriptions, nomenclatural summaries, habitats, and distributional records, and observations.

Gypsophila paniculata L. (baby’s breath), an ornamental of Eurasian origin introduced into western Canada more than 80 years ago, was studied to evaluate its potential as a weed. It was found as an adventive species or garden escape at 50 locations in Saskatchewan. Mature plants are able to withstand large fluctuations in rainfall and live for many years. Although this species does not lower the yield of competing forage grasses, it has a low feed value and is not measurably reduced in vigor by mowing. Heavy, continuous grazing suppresses the growth of mature plants and prevents the establishment of seedlings, while annual cultivation at a depth which severs the caudex from the root kills the plants.

The seasonal and numerical distribution of seeds of adventive species entering the central 50—m zone of the irradiated forest facility of Brookhaven National Laboratory was studied by the exposure plate method. Adventive seeds were collected from 15 August to 10 December 1963 and 7 May to 1 September 1964 and the cumulative total per hectare noted. The species found on the traps matched fairly well those species established in the study area, suggesting that successional patterns in the 50—m zone are dependent on the availability of aerially borne seeds from surrounding areas. See full-text article at JSTOR

There has been further evidence of relations between number of chromosomes and degree of polyploidy with ecological preferences, both within plant species and between closely related species (Gustafsson, I947), since Lovkvist (I947) first reported a relation between chromosome number and ecological habitat in Cardamine pratensis. A recent survey of chromosome races in Britain has indicated, for instance, that generally an increasing degree of polyploidy goes with types preferring wetter habitats (Haskell, I95 i), and there may be differences of pH tolerances in closely related species of different ploidy (Howard, I95I). The flora of Britain possesses several genera with two species only; among these are some genera, such as Bidens, which contain one diploid and one polyploid species. Plotting diploids and polyploids against each other on the basis of their vice-county distributions has shown that relative distribution of the types is at random (Haskell, 1952). Yet as Britain possesses many adventive species, whose dates of introduction are fairly certain, it would be interesting to watch the comparative spread of a diploid and polyploid species within a single genus. So far this has not been possible. Attention has recently been drawn by Brenan (I939) to a new adventive species of Galinsoga, G. ciliata (synonym G. quadriradiata), whose morphological features and habits are very much like those of G. parviflora, a species already well acclimatized in Britain. As the description of the new species by both Brenan (I939) and Lousley (I950) suggested to us that it might be a polyploid, a cytological investigation was therefore made of both Galinsoga species. At the same time it was hoped that the information would be of value in studies of chromosomes and ecological distribution of plant species in Britain. History of Galinsoga in Britain

As UNDERSTOOD by Schulz (1924), Descurainia Webb & Berthelot is a natural assemblage of 43 species of annual and biennial cruciferous plants. Dething (1939) revised the North American species of the genus. Interpreting the species broadly on morphologic, ecologic, and geographic evidence, he regards "the subspecies as the product of the selective action of a particular environment" and, accordingly, recognized for Descurainia in North America 9 native and I adventive species. (Fernald [1940] claims that Detling, at least in some instances, incorrectly used the term subspecies "in the sense of the long-established term varietas.") Southwestern United States is the distributional center of the native representatives of the genus. Dr. LeRov E. Detling sent seeds collected from wild plants of four species and ten subspecies of Descurainia. Plants from those seeds were grown in the Botanical Gardens of the University of Michigan. Chromosomes of the plants were counted at metaphase in leaf smears prepared by the method of Baldwin (1939). CHROMOSOMES AND THE PLANTS.-The chromosomes of Descurainia are uniformly small. The chromosome numbers form, with the exception of one report, a regular polyploid series founded on 7. Previous workers have published chromosome numbers for four species of the genus. Two of those species are South American: D. Cumtngiana (Fisch & Meyer) Prantl, with 14 somatic (Manton, 1932), 7 gametic (Jaretzky, 1932) chromosomes; D. myriophylla (Willd.) Fries, with 14 and, in some cells, 28 somatic chromosomes (Manton, 1932). The North American representatives of Descurainia for which chromosome numbers are known are given below as interpreted systematically by Detling. Data on geographic occurrence are taken from that author. Detling's herbarlum numbers and the places of collection are put in brackets. D. Sophia (L.) Webb, the type species, is an annual or biennial plant of the Old World and is now distributed throughout the United States, Canada, and Alaska. Manton (1932) reported for the species 28 and, in some cells, 56 somatic chromosomes. Jaretzky (1932) found 14 gametic chromosomes, Mayor (1934) emphasized the difficulty of counting the chromosomes of this plant and provisionally reported 10 gametic, 20 somatic chromosomes for the species, designated by him Sisymbrium Sophia L. The present writers determined a 2n-number of 28 for the species [IDetling 2217, Mountain Home, Idaho] (fig. 1). D. Richardsonii (Sweet) Schulz is biennial andoccurs, for the most part, in the mountains of the western Unlted States; one subspecies is in the northern plains. Two collections of subspecies vis' Received for publication July 17, 1940. Papers from the Department of Botany of the University of Michigan, No. 723. cosa (Rydb.) Detl. [Detling 2257, Targhee Pass, Idaho; Detling 2213, Hilgard, Oregon] were found dulring this study to have 14 somatic chromosomes (fig. 2), subspecies procera (Greene) Detl. [Detling 2263, Howard Springs, Targhee Pass, Idaho) to have a 2n-number of 28 (fig. 3), and subspecies incisa (Engelm.) Detl. [Detling 2380, Flagstaff, Arizona], a 2n-number of 42 (fig. 4). It is clear that these subspecies are separated by polyploid differences. Consideratlon of the ranges given by Detling shows that the diploid viscosa and the hexaploid incisa occupy geographic areas of approximately the same magnitude, the latter subspecies being more southern in its occurrence but extending into the range of viscosa; and that, of these three subspecies, the tetraploid procera has the most restricted range and occurs almost entirely within the region where both incisa and viscosa are found. D. obtusa (Greene) Schulz is an aggregate of strict, coarse, biennial plants mostly in the mountains or on the high plateaus of southwestern United States and northern Mexico. The present authors found that subspecies typica Detl. [Detling 2381 Williams, Arizona] has 2n=14 (fig. 5), and that subspecies brevisiliqua Detl. [Detling 2375, Gonzales, New Mexico, the type collectionDetling 2374, Thoreau, New Mexico] has 2n=42 (fig. 6). The diploid typica has a greater geographic range than the hexaploid brevisiliqua. Most of the range of the diploid is south of that of the hexaploid. D. pinnata (Walt.) Britt. is a group of annual plants. "Evolution within this species seems to have followed two distinct lines, giving rise to one complex of subspecies in the hot arid regions of the Southwest and another complex in the more northern cooler and frequently moister regions of the Rocky Mountains, the Pacific Northwest and Canada" (Detling, 1939). The two complexes intergrade geographically and morphologicallv. Sometimes the northern association is segregated as D. brachycarpa (Richards) Schulz. The subspecies ha-ltctorum (Cockerell) Detl. includes both glandular and non-glandular plants; the plants differ in chromosome number. Cockerell (1901) gave specific rank to the non-glandular one. The authors found the glandular plant [Detling 2291, Boulder, Wyoming ; Detling 2300, Red Desert, Wyoming] to have 42 somatic chromosomes (fig. 7), the non-glandular one [Detling 2360, Mesa Verde, Colorado] to have 28 somatic chromosomes (fig. 8). Likewise, subspecies glabra (Woot. & Standl.) Detl. [Detling 2387, Mojave Desert, California] was discovered to have a 2n-number of 28 (fig. 9). Subspecies Menziesii (DC.) Detl. was investigated by Manton (1932), who gave the plant specific status and reported for it 28 somatlc chromosomes. The present authors counted the chromosomes of three other subspecies: subspecies intermedia (Rydb.) Detl.

In connection with the study of the Senecio lautus complex in Australia, the author realized that some specimens, identified as S. lautus Willd. or S. platylepis DC., were in fact very different from either of these taxa. A representative specimen was sent to Kew for verification. Dr. R. Melville, who kindly examined the material, is of the opinion that the specimen probably represents a native species. But as it could have been an adventive species, he checked the South African material also but did not find anything similar. It, therefore, appears to be an undescribed native species. It has been named here as Senecio tuberculatus Ali, indicating the tuberculate nature of the fruit, which seems to be unique.