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Cavea is a low perennial herbaceous plant that is assigned to the family Asteraceae. Cavea tanguensis is currently the only species assigned to this genus. It has a basal rosette of entire, slightly leathery leaves, and stems of 5–25 cm high, topped by bowl-shaped flower heads with many slender florets with long pappus and purplish corollas. The vernacular name in Chinese is 葶菊 (ting ju). It grows high in the mountains of China (Sichuan), Tibet, India (Sikkim), and Bhutan, and flowers in July and August.[2]
Cavea is a perennial herb with stout, woody and mostly branched rootstocks of 10–30 cm long, which carry a basal leaf rosette and unbranching stems that carry some smaller leaves, bracts and flower heads.[2]
The erect unbranching stems are stout and 5–25 cm high. The leaves in the basal rosette are somewhat leathery or even fleshy, the underside with many or few brownish glandular hairs, elongated spoon-shaped, 1+1⁄2–6 or exceptionally 12 cm long and 1⁄2–1 cm wide, at the base gradually narrowing to the main vein, the edge with some teeth far apart, and a blunt tip or almost pointy. The leaves on the stem have brownish glandular hairs, with some saw-like teeth and a blunt tip. The lower leaves on the stem are 3–6 cm long and 1⁄2–1¼ cm wide. Leaves become smaller and less leathery or fleshy further up, with the highest bract-like, up to 1+1⁄2 cm, almost vertically oriented and enveloping the base of the flower heads.[2]
Flower heads mostly contain relatively few male florets at the centre, encircled by many more female florets. However solely female flower heads also occur, and individual plants may even produce only female flower heads. The flower heads are individually set at the end of the branches, bowl-shaped and mostly 3–3+1⁄2 cm across. The involucre is 1+1⁄2–2 cm high, nearly reaching the mouth of the florets, with four to five whorls of leaf-like bracts, the outermost bracts largest, which are long to very long ovate in shape linear-oblong or obovate-lanceolate, their margin with some glandular hairs, and a stump to pointy tip. The common base of the floret is flat or somewhat convex, and is without bracts subtending individual florets. Each flower head contains a hundred to two hundred very slender disk florets. There are usually, twenty to thirty male florets at the centre of a flower head, which are tube- to bell-shaped, with five lobes, the tube being about 4+1⁄2 mm long, and the free part of the lobes about 4 mm long. In the male florets, the stigma does not split into lobes. The sterile cypselae are about 11 mm long, hairless except for one whorl of pappus hairs of about 5 mm at the tip. The female florets are purplish in color, tube-shaped, densely covered in hard white hairs, with a tube of about 7 mm long and lobes of less than ¼ mm. In the female florets, the stigmas have two lobes, the lobes being exserted inside the corolla tube. The cypselae in the female florets are slender, angular cylindrical, 5–6 mm, set with dense bristles and two whorls of about fifty rough, purple pappus hairs of about 7+1⁄2 mm. Flowers are present in July and August, while ripe fruits can be found in September and October.[2]
The pollen grains are about 35 μm in diameter, slightly flattened at the poles, with three longitudinal slits that suddenly stop near the poles. The surface is densely covered in conical spines of 2–4+1⁄2 μm high and 1+3⁄4–2+1⁄2 μm wide at the base, slightly perforated at base, and with pointy tips.[3]
The species was initially described in 1910 as Saussurea tanguensis by James Ramsay Drummond, a British civil servant and amateur botanist living in India. However, William Wright Smith and John Kunkel Small in 1917 considered it too different from other Saussurea species and erected the new genus Cavea for it.[2] The placement of Cavea within the daisy family has been difficult. In older literature it was placed with the Inuleae, however in 1977 it was removed from that tribe because the morphology of the pollen was too different. Arne Anderberg considered the species might be a relative of Saussurea, which he placed in the Cardueae. C. Jeffrey in 2007 had reservations, but preliminary placed it in the Cardueae. Recent genetic analysis suggests it could be best assigned to the Gymnarrhenoideae. Few morphological features would support this assignment, other than both having two types of flower heads and sharing a tendency towards dioecism.[4] Both also have basal leaf rosettes, stretched leaves, with few spaced teeth on the margin, and both lack spines and latex.
Gymnarrhena micrantha is now considered the sister taxon of Cavea tanguensis, who together constitute the tribe Gymnarrheneae and the subfamily Gymnarrhenoideae.[4][5]
Based on recent genetic analysis, it is now generally accepted that the Pertyoideae subfamily is sister to a clade that has as its basal member the Gymnarrhenoideae, and further consists of the Asteroideae, Corymbioideae and Cichorioideae. These three subfamilies share a deletion of nine base-pairs in the ndhF gene which is not present in Gymnarrhena micrantha. Current insights in the relationships of Cavea and Gymnarrhena to the closest Asterid subfamilies is represented by the following tree.[4][5]
subfamily Pertyoideae
subfamily GymnarrhenoideaeCavea tanguensis
subfamily Cichorioideae
subfamily Corymbioideae
subfamily Asteroideae
Cavea is named after George Cave, who was the curator of the Lloyd's Botanical Garden in Darjeeling, and who collected many new plants from all over Sikkim.[6]
This plant can be found in southwestern Sichuan, Tibet, Bhutan, and Sikkim.[2]
Cavea grows on gravelly substrate near glaciers and streams at altitudes between 4000 and 5100 m.[2]
Leaves are used on wounds, and to suppress fever. In traditional Tibetan medicin, the species is known as ming-chen-nag-po.[7][8]
Cavea is a low perennial herbaceous plant that is assigned to the family Asteraceae. Cavea tanguensis is currently the only species assigned to this genus. It has a basal rosette of entire, slightly leathery leaves, and stems of 5–25 cm high, topped by bowl-shaped flower heads with many slender florets with long pappus and purplish corollas. The vernacular name in Chinese is 葶菊 (ting ju). It grows high in the mountains of China (Sichuan), Tibet, India (Sikkim), and Bhutan, and flowers in July and August.
Cavea tanguensis (J.R.Drumm.) W.W.Sm. & J.Small, 1917 è una pianta angiosperma dicotiledone appartenenti alla famiglia delle Asteraceae. Cavea tanguensis è anche l'unica specie del genere Cavea W.W.Sm. & J.Small, 1917[1][2][3]
Il nome del genere (Cavea) è stato dato in onore di George Cave, che era il curatore del Lloyd's Botanical Garden a Darjeeling e che raccolse molte nuove piante da tutto il Sikkim.[4]
Sono piante erbacee perenni, talvolta sono dioiche e/o monoiche. Possiedono un robusto e ramificato rizoma. I fusti sono eretti e semplici. Le foglie, a disposizione alternata e per lo più basali, hanno delle forme ovato-lanceolate e un picciolo distinto (quelle cauline sono più o meno sessili); la superficie è pubescente.[5][6][7][8][9]
Le infiorescenze sono composte da larghi capolini campanulati, terminali e solitari. I capolini, eterogami e disciformi oppure omogami e unisessuali, sono formati da un involucro a forma più o meno cilindrica composto da diverse brattee disposte su più serie in modo embricato e scalato all'interno delle quali un ricettacolo fa da base ai fiori. Le brattee hanno una consistenza fogliacea. Il ricettacolo è piano (o convesso), faveolato e privo di pagliette ("ricettacolo nudo").
I fiori sono ermafroditi, tetraciclici (calice – corolla – androceo – gineceo) e pentameri. I fiori si dividono in regolari (ermafroditi-femminili e fertili, molto numerosi), quelli esterni nei capolini eterogami e funzionalmente staminali (20 - 30 fiori solo maschili e sterili), quelli interni nei capolini eterogami.
, [C (5), A (5)], G 2 (infero), achenio[10]
Il frutto è un achenio con pappo. L'achenio ha una forma oblunga, affusolata o subquadrangolare; la superficie è ricoperta densamente da peli multicellulari doppi. Il pappo è formato da una serie di setole barbate color porpora nei fiori maschili (nei fiori femminili le serie sono due). Gli acheni dei fiori staminali (quelli interni di una capolino eterogamo) sono vestigiali con un pappo formato da alcune setole apicali leggermente espanse.
La distribuzione delle piante di questa specie è relativa all'India del nord-est e alla Cina del sud-ovest.
La famiglia di appartenenza di questa voce (Asteraceae o Compositae, nomen conservandum) probabilmente originaria del Sud America, è la più numerosa del mondo vegetale, comprende oltre 23.000 specie distribuite su 1.535 generi[11], oppure 22.750 specie e 1.530 generi secondo altre fonti[12] (una delle checklist più aggiornata elenca fino a 1.679 generi)[13]. La famiglia attualmente (2021) è divisa in 16 sottofamiglie.[1]
Il genere di questa voce appartiene alla tribù Gymnarrheneae della sottofamiglia Gymnarrhenoideae. Questa assegnazione è stata fatta solo ultimamente in base ad analisi di tipo filogenetico sul DNA delle piante del genere. In precedenza, anche se alcuni caratteri lo accomuna al gruppo delle Carduoide, era descritto all'interno delle saussuree (vedi il sinonimo Saussurea tanguensis J.R.Drumm.) o posizionato vicino alle Inuleae[14]; in altre occasioni era definito come "incertae sedis" tra i generi della tribù Cardueae.[8][9]
Un carattere significativo per questa specie è la superficie stigmatica divisa in due bande.[1]
Cavea tanguensis (J.R.Drumm.) W.W.Sm. & J.Small, 1917 è una pianta angiosperma dicotiledone appartenenti alla famiglia delle Asteraceae. Cavea tanguensis è anche l'unica specie del genere Cavea W.W.Sm. & J.Small, 1917
Cavea é um género botânico pertencente à família Asteraceae.[1]
Cavea é um género botânico pertencente à família Asteraceae.
葶菊属（学名：Cavea）是菊科下的一个属，为多年生草本植物。该属仅有葶菊（Cavea tanguensis）一种，分布于锡金至中国西南部。[1]
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