Daucinae

Wild carrot Daucus carota, copyright Paul Asman and Jill Lenoble.

Belongs within: Scandiceae.

The spread of carrots
Published 30 November 2020

Carrots are one of the staple vegetables in this part of the world as well as in a great many others. Indeed, Wikipedia informs us that about forty million tonnes of carrots and turnips were produced worldwide in 2018, and I would have to think that carrots accounted for the greater part of that number. Wild carrots are also a widespread weed that can commonly be seen growing in disturbed, open habitats such as roadside verges. This post is about the group of plants that carrots typify, the subtribe Daucinae.

Wild carrot Daucus carota in flower, copyright Cwmhiraeth.

Daucinae is a subgroup of the plant family Apiaceae, historically known as the Umbelliferae. The latter name refers to the characteristic production of flowers in dense, flat-topped inflorescences known as umbels. Anyone who is familiar with the appearance of carrot flower-heads is familiar with the form of an umbel; the wild form of carrot is often known as “Queen Anne’s lace” in reference to said appearance. The fruit of Apiaceae species is a schizocarp, a dry fruit that splits at maturity into segments (called mericarps), each containing a single seed, that are dispersed independently. In Daucinae and related group of umbellifers, the mericarps carry longitudinal ribs, both primary ribs containing a vascular bundle and secondary ribs without. The secondary ribs of Daucinae are often modified to form broad wings or curved spines that function in the mericarp’s dispersal.

Broad-leafed sermountain Laserpitium latifolium seedheads, showing wings, copyright Krzysztof Ziarnek, Kenraiz.

Historically, these differences in mericarp morphology have been used to assign the species bearing them to different tribes. However, more recent phylogenetic analyses have indicated that changes between wings and spines have occurred on multiple occasions due to changes in mode of dispersal (Wojewódzka et al. 2019). Mericarps bearing wings are generally anemochorous (dispersed by wind) whereas those bearing spines are epizoochorous (carried by animals, such as stuck to a mammal’s fur). The distinction is not 100% immutable: winged seeds may sometimes get caught in fur, spined seeds may be carried slightly further by wind than smooth ones. Phylogenies indicate that anemochory was the ancestral condition for Daucinae, retained in genera such as Laserpitium and Thapsia. Epizoochorous species do not form a single clade within the Daucinae (indeed, the genus Daucus includes both anemochorous and epizoochorous species) but it is unclear to what degree epizoochory arose on multiple occasions versus reversions to anemochory from epizoochorous ancestors. Two species of Daucinae, Daucus dellacellae from the Cyrenaica region of northern Africa and Cryptotaenia elegans from the Canary Islands, have neither spines nor wings on their mericarps which are therefore dispersed by gravity alone. In the case of C. elegans, at least, it has been suggested that it evolved from epizoochorous ancestors that lost the spines because of the absence of suitable dispersing animals on the islands (Banasiak et al. 2016).

Though the carrot Daucus carota is perhaps the most widely grown daucine umbellifer, it is not the only economically significant member of the group. Cumin Cuminum cyminum, whose seeds are widely used as a spice, is either a daucine or a close relative of daucines (Banasiak et al. 2016). Cuminum does differ from other daucine genera in that its mericarps lack appendages on the secondary keels, however. Gladich Laser trilobum is a perennial found growing in Europe and western Asia whose seeds are used as a condiment. Certain species of the deadly carrot genus Thapsia have a history of medicinal usage though, as their vernacular name suggests, their use does require caution. One species, T. garganica, is among the suggested candidates for the identity of the mysterious silphium of the Romans (used, among other things, as an abortifacient) though perhaps not the most likely contender. That, perhaps, is a story for another time.

Systematics of Daucinae
Daucinae [Dauceae, Daucidae]DK-DW00
|--Orlaya Hoffmann 1814DK-DW00, PC85 [Orlayeae]
| |--O. daucoidesPT98
| `--O. grandifloraB28
`--+--Laserpitium Linnaeus 1753DK-DW00, PC85
| |--L. hispidumDK-DW00
| `--L. latifoliumC55
`--+--+--Agrocharis Hochstetter 1844DK-DW00, PC85 [Agrocharideae]
| | `--A. incognitaDK-DW00
| `--+--‘Daucus’ bicolorBGS05
| |--‘Daucus’ durieuaBGS05
| |--‘Daucus’ montanusBGS05
| `--‘Daucus’ pusillusDK-DW00
`--+--Pachyctenium mirabileBGS05
`--Daucus Linnaeus 1753DK-DW00, A61
|--*D. carota Linnaeus 1753BGS05, PL04
| |--D. c. ssp. carotaDK-DW00
| `--D. c. ssp. sativusDK-DW00
|--D. aureusBGS05
|--D. australisD03
|--D. crinitusBGS05
|--D. glochidiatus [=Scandix glochidiata Labill. 1804; incl. D. brachiatus Sieb. in DC. 1830]A61
|--D. guttatusPT98
|--D. involucratusPT98
|--D. minusculus [=Pseudorlaya minuscula]BGS05
|--D. muricatusBGS05
`--D. pumilus [=Pseudorlaya pumila; incl. P. pumila ssp. microcarpa]BGS05

Daucinae incertae sedis:
Ammodaucus leucotrichusDK-DW00, D17
|--A. l. var. leucotrichusD17
`--A. l. var. brevipilusD17
Cuminum Linnaeus 1753DK-DW00, PC85 [Cumineae]
`--C. cyminumD17
Laser Borkhausen ex Gaertner, Meyer & Scherbius 1799 [Laserinae]PC85
`--L. trilobumDK-DW00
MelanoselinumDK-DW00
MoniziaDK-DW00
Polylophium panjutiniiDK-DW00
Thapsia Linnaeus 1753DK-DW00, PC85 [Thapsieae]
`--T. garganicaPT98

*Type species of generic name indicated

References

[A61] Allan, H. H. 1961. Flora of New Zealand vol. 1. Indigenous Tracheophyta: Psilopsida, Lycopsida, Filicopsida, Gymnospermae, Dicotyledones. R. E. Owen, Government Printer: Wellington (New Zealand).

Banasiak, Ł., A. Wojewódzka, J. Baczyński, J.-P. Reduron, M. Piwczyński, R. Kurzyna-Młynik, R. Gutaker, A. Czarnocka-Ciecura, S. Kosmala-Grzechnik & K. Spalik. 2016. Phylogeny of Apiaceae subtribe Daucinae and the taxonomic delineation of its genera. Taxon 65 (3): 563–585.

[BGS05] Banfi, E., G. Galasso & A. Soldano. 2005. Notes on systematics and taxonomy for the Italian vascular flora. 1. Atti Soc. It. Sci. Nat. Museo Civ. Stor. Nat. Milano 146 (2): 219–244.

[B28] Betrem, J. G. 1928. Monographie der Indo-Australischen Scoliiden mit zoogeographischen Betrachtungen. H. Veenman & Zonen: Wageningen.

[C55] Candolle, A. de. 1855. Géographie Botanique Raisonée: Ou exposition des faits principaux et des lois concernant la distribution géographique des plantes de l’époque actuelle vol. 1. Librairie de Victor Masson: Paris.

[D17] Diels, L. 1917. Beiträge zur Flora der Zentral-Sahara und ihrer Pflanzengeographie. Nach der Sammelausbeute des Freiherrn Hans Geyr von Schweppenburg. Botanische Jahrbücher für Systematik, Pflanzengeschichte und Pflanzengeographie 54 (Beiblatt 120): 51–155.

[DK-DW00] Downie, S. R., D. S. Katz-Downie & M. F. Watson. 2000. A phylogeny of the flowering plant family Apiaceae based on chloroplast DNA rpl16 and rpoC1 intron sequences: towards a suprageneric classification of subfamily Apioideae. American Journal of Botany 87 (2): 273–292.

[PT98] Panitsa, M., & D. Tzanoudakis. 1998. Contribution to the study of the Greek flora: flora and vegetation of the E Aegean islands Agathonisi and Pharmakonisi. Willdenowia 28: 95–116.

[PC85] Pimenov, M. G., & L. Constance. 1985. Nomenclature of suprageneric taxa in Umbelliferae/Apiaceae. Taxon 34 (3): 493–528.

[PL04] Pohl, G., & I. Lenski. 2004. Zur Verbreitung und Vergesellschaftung von Pennisetum orientale Rich. in Nordeuböa (Griechenland) (Poaceae, Paniceae). Senckenbergiana Biologica 83 (2): 209–223.

Wojewódzka, A., J. Baczyński, Ł. Banasiak, S. R. Downie, A. Czarnocka-Ciecura, M. Gierek, K. Frankiewicz & K. Spalik. 2019. Evolutionary shifts in fruit dispersal syndromes in Apiaceae tribe Scandiceae. Plant Systematics and Evolution 305: 401–414.

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