Monographs Details: Thlaspi montanum L.
Authority: Holmgren, Patricia K. 1971. A biosystematic study of North America Thlaspi montanum and its allies. Mem. New York Bot. Gard. 21: 1-106.
Description:Distribution and Ecology - Representative specimens of typical T. alpestre are as follows: CZECHOSLOVAKIA: Bohemia centralis, Klicany prope Kfivoklat, 9 May 1929, J. Dostdl s. n. (NY); Moravia centrahs, Ivancice, 28 Apr 1968, F. Cernoch s. n. (NY); Slovacia centralis, monies Nizke Tatry (Tatra Minor), 24 May 1963, A. Hrabetovd 1412 (MO). ENGLAND: Durham, Winch Bridge, Upper Teesdale, 29 Jun 1909, T. W Edmondson 4742 (NY). FINLAND: Nylandia, par. Esbo, 20 May 1910, H. Lindberg 690 (NY); Nylandia, Helsingfors, 9 May 1960, I. Teissala & A. Nordstrom s. n. (NY); Oulu, T. Ulvinen s. n. (WTU). GERMANY: vallee de la Nahe pres de Kreuznach, 15 Mar 1859, F. Schulz & C. Vaupel s. n. (NY); Wiesbaden, May 1875, A. N . Levy s. n. (NY). NETHERLANDS: Limburg, J. T. Henrard s. n. (NY). SCANDINAVIA: A. Nordstrom s. n. (WTU); A. Lindstrom s. n. (GH). SWEDEN: Norrkoping, Elmquist s. n. (NY); Uppsala, Jul 1885, Eroding s. n. (NY); Vastergotland, Lerdala, 6 May 1937, O. Bokman s. n. (NY); Ostergdtland, Linkoping, 1869, P. Dusen s. n. (NY); Gotland, 22 May 1932, E. T. Fries s. n. (NY). SWITZERLAND: Jura, La Dole, May 1870, H. Bernet s. n. (NY).
Thlaspi alpestre, as revealed by live plants in the greenhouse, differs from T. montanum in its smaller flowers, usually fewer stems, slender taproot without a branched caudex, gradually flaring petals, stamens from longer to slightly shorter than the petals, biennial or short-lived perennial habit, and its predominant tendency toward self-pollination.
Dr. Arthur Cronquist examined the type specimens of T. alpestre and T. montanum in Europe. He reports that there are four specimens of T. montanum in the Linnaean herbarium, all in flower; three of these are marked as ''montanum" in Linnaeus' own hand. One of the specimens is comprised of two fragmentary plants, each consisting of a stem with basal leaves and a slender, stoloniform base. The basal leaves range from 2-3.8 cm long and from 5-8 mm wide. The sepals are 2-2.7 mm long and the petals are about 6 nam, exceeding the stamens. One of the other specimens has smaller basal leaves up to about 1.2 cm long and 5 mm wide. Another specimen has a style about 1.5 mm, sepals 2 m m , and petals about 5 mm long. Cronquist states that a specimen collected in Idaho (Clark 48, WTU), which I had sent him for comparison with European material, matches very closely the Linnaean material of T. montanum.
The type of T. alpestre was not suggestive of any New World Thlaspi to Cronquist. The plant was said to be single-stemmed from a biennial or short-lived perennial base and to have a taproot surmounted by an unbranched crown. The flowers are smaller than in T. montanum; the fruits are immature. Approximately two years after Cronquist examined the type specimens for me, I saw photographs of them from DAO. My observations concur with those of Cronquist.
Figure 55 compares T. alpestre and T. montanum on purely quantitative features. As seen by this polygonal graph, the only quantitative features separating these species are the length and width of the petals and length of the style. The length of the sepals is usually shorter and the silicles often narrower in T. alpestre. All of the other radii on the graph show random variability.
Using T. alpestre as the seed parent in crosses with T. montanum, sterile hybrids are produced. However, using T. montanum as the seed parent in crosses with T. alpestre, crossability is low but fertility (as judged by pollen stainability) is high (95-99%). Crosses between T. parviflorum and T. alpestre produce nearly sterile F1's (less than 1% stainable pollen). Back crosses to T. alpestre produced two sterile plants and one partially fertile one (31% stainable pollen).
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