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Brassica chinensis var. parachinensis

(Choy Sum)

Common Names

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Common Names in English:

Choy Sum, Phak Kwang Tung

Description

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Genus Brassica

Herbs annual , biennial, or perennial , rarely subshrubs or shrubs , often glaucous. Trichomes absent or simple . Stems erect or ascending , simple or branched, leafy or rarely leafless. Basal leaves petiolate , rosulate or not, simple, entire, dentate , lyrate-pinnatifid, or pinnatisect . Cauline leaves petiolate or sessile, base cuneate, attenuate, auriculate , sagittate , or amplexicaul , margin entire, dentate, or lobed . Racemes ebracteate , elongated in fruit. Fruiting pedicels ascending, divaricate , or reflexed . Sepals ovate or oblong , erect, ascending, or rarely spreading , base of lateral pair saccate or not. Petals yellow, rarely white or pink; blade obovate , spatulate , or rarely oblanceolate , apex obtuse or emarginate ; claw distinct , subequaling or longer than sepals. Stamens 6, tetradynamous ; anthers ovate or oblong, obtuse at apex. Nectar glands 4, median and lateral, rarely 2 and lateral. Ovules 4-50 per ovary. Fruit dehiscent siliques, linear or rarely oblong, terete , 4-angled, or latiseptate , sessile or shortly stipitate , segmented ; valvular segment dehiscent , 4-46-seeded, longer than terminal segment, smooth or torulose , valves with a prominent midvein and obscure lateral veins; terminal segment seedless or 1(-3) -seeded; replum rounded ; septum complete , translucent or opaque , veinless or with a distinct midvein; style obsolete or distinct; stigma capitate, entire or 2-lobed. Seeds uniseriate or rarely biseriate , wingless, globose or rarely oblong, plump or rarely slightly flattened; seed coat reticulate , mucilaginous or not when wetted; cotyledons conduplicate .

About 40 species: primarily in the Mediterranean region, especially SW Europe and NW Africa; six species in China.

Brassica includes the most important vegetables and oilseed plants of the Brassicaceae, and China is the center where human selection has created numerous cultivars, more so than elsewhere in the world. Most of these were described by Liberty H. Bailey as species based primarily on minor differences in leaf morphology. In fact, Bailey (Gent. Herb. 1: 53-108. 1922; 2: 211-267. 1930; 4: 319-330. 1940) recognized 25 crop species of Brassica (including two presently assigned to Sinapis and ten as "new"), of which 23 species names clearly belong to only six species (nos. 1-5 of the present account, plus B . carinata A. Braun) . Critical study of all of Bailey's types by one of the present authors (Al-Shehbaz), along with comprehensive cytological, crossing, and molecular studies conducted by numerous researchers over the past several decades, reveal that all of Bailey's "species and infraspecific taxa" clearly belong to four species: B. juncea (2n = 36), B. napus (2n = 38), B. oleracea (2n = 18), and B. rapa (2n = 20) .

Cultivated forms (or taxa) with the same chromosome number are indistinguishable in fruit, seed, and flower characters, and they interbreed freely and produce fully fertile offspring. Furthermore, such forms often lose their identity outside of cultivation and become basically indistinguishable from the weedy forms of the species to which they belong. Because the Chinese Brassica are maintained only in cultivation as distinct crops and have well-established Chinese names , they have been recognized in most of Chinese floras as distinct species. However, they are best treated as varieties, just as the numerous and morphologically far more diversified forms of B. oleracea are recognized worldwide (see below) . As many as 18 species of Brassica have been recognized in China, but the easternmost native range of the genus hardly reaches C Asia. On the basis of the enormous array of cultivated infraspecific taxa of B. juncea and B. rapa in China, it is evident that these two species have been domesticated there for thousands of years.[1]

Physical Description

Flowers: Bloom Period: April, May. • Flower Color: yellow

Size/Age/Growth

Size: 6-12" tall.

Biology

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Growth

Culture: Space 3-6" apart.

Soil: Minimum pH: 5.6 • Maximum pH: 7.5

Sunlight: Sun Exposure: Full Sun .

Taxonomy

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Similar Species

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Members of the genus Brassica

ZipcodeZoo has pages for 1258 species, subspecies, varieties, forms, and cultivars in this genus. Here are just 100 of them:

B. alboglabra (Chinese Kale) · B. campestris var. chinensis 'Bangluang' (Bok Choy) · B. campestris var. chinensis 'Hong Tae' (Bok Choy) · B. campestris var. chinensis 'Kesorn' (Bok Choy) · B. campestris var. chinensis 'Kokaew' (Bok Choy) · B. campestris 'Canton Bok' (Dwarf White Stem Pak Choy) · B. campestris 'Ho Tau Bok' (Dwarf White Stem Pak Choy) · B. carinata (Abyssinian Mustard) · B. carinata 'Sincron' (Abyssinian Cabbage 'sincron') · B. chinensis (Pak Choi) · B. chinensis var. parachinensis (Choy Sum) · B. chinensis var. parachinensis 'Elite 70 Day' (Choy Sum) · B. chinensis var. parachinensis 'Golden 49' (Choy Sum) · B. chinensis var. parachinensis 'Green 70 Day' (Choy Sum) · B. chinensis var. parachinensis 'Green 80 Days' (Choy Sum) · B. chinensis var. parachinensis 'Green Kuang Futsoi' (Choy Sum) · B. chinensis var. parachinensis 'Late Green' (Choy Sum) · B. chinensis var. parachinensis 'Welcome' (Choy Sum) · B. chinensis var. rosularis 'Wuta 1' (Tahtsai) · B. chinensis var. utilis 'Fuji Green' (Bok Choi) · B. chinensis var. utilis 'Green Fortune' (Bok Choi) · B. chinensis var. utilis 'Happy Tropic' (Bok Choi) · B. chinensis var. utilis 'Long White Petiole' (Bok Choi) · B. chinensis var. utilis 'Luxiu' (Bok Choi) · B. chinensis var. utilis 'Shanghai' (Bok Choi) · B. chinensis var. utilis 'South White' (Bok Choi) · B. chinensis var. utilis 'Yellow Flowering Purple Pak Choi' (Bok Choi) · B. chinensis var. utilis 'Yunu 1' (Bok Choi) · B. cretica (Mustard) · B. elongata (Elongated Mustard) · B. fruticulosa (Mediterranean Cabbage) · B. juncea (Chinese Mustard) · B. juncea napiformis (Oriental Mustard) · B. juncea var. capitata 'Bau-Sin' (Heading Mustard) · B. juncea var. capitata 'Domino' (Heading Chinese Mustard) · B. juncea var. capitata 'Kungfu' (Heading Mustard) · B. juncea var. capitata 'Late Bau Sin' (Heading Chinese Mustard) · B. juncea var. capitata 'Max' (Heading Chinese Mustard) · B. juncea var. juncea (India Mustard) · B. juncea var. multiceps 'Jiu Tou Niao' (Chinese Mustard) · B. juncea var. multiceps 'Qm Red' (Chinese Mustard) · B. juncea var. rugosa (Broad-Leaved Mustard) · B. juncea var. rugosa 'Old Fashion' (Broad-Leaved Mustard) · B. juncea var. rugosa 'Zaar' (Broad-Leaved Mustard) · B. juncea var. tumida 'Er Choy' (Tsa Tsai) · B. juncea var. tumida 'North Round' (Tsa Tsai) · B. juncea 'Early Mizuna' (Mustard Greens) · B. juncea 'Florida Broadleaf' (Mustard) · B. juncea 'Golden Streaks' (Mustard) · B. juncea 'Green in Snow' (Mustard) · B. juncea 'Green Wave' (Mustard) · B. juncea 'King Mustard' (Mustard) · B. juncea 'Kyona Mizuna' (Mustard Greens) · B. juncea 'Osaka Purple' (Red Mustard) · B. juncea 'Red Giant' (Broad-Leaved Mustard) · B. juncea 'Savanna' (Broad-Leaved Mustard) · B. juncea 'Southern Giant Curled' (Mustard) · B. juncea 'Suehlihung No.2' (Mustard) · B. juncea 'Thai Jute' (Mustard Greens) · B. juncea 'Thai Mustard' (Mustard Greens) · B. juncea 'Yukina Savoy' (Mustard Greens) · B. muralis (Annual Wallrocket) · B. napobrassica 'American Purple Top' (Rutabaga) · B. napobrassica 'Angela' (Rutabaga) · B. napobrassica 'Laurentian' (Rutabaga) · B. napobrassica 'Ruby' (Rutabaga) · B. napus (Canadian Turnip) · B. napus var. napus (Rape) · B. napus var. oleifera (Rape) · B. napus var. pabularia (Siberian Kale) · B. napus var. pabularia 'Red Russian' (Siberian Kale) · B. napus '99ey030' (Oil Seed Rape '99ey030') · B. napus '99ey030 Ms' (Oil Seed Rape '99ey030 Ms') · B. napus 'Afflux' (Oil Seed Rape 'afflux') · B. napus 'Ajjax' (Oil Seed Rape 'ajjax') · B. napus 'Alcazar' (Oil Seed Rape 'alcazar') · B. napus 'Amillia' (Oil Seed Rape 'amillia') · B. napus 'Best of All' (Rutabaga) · B. napus 'Boheme' (Oil Seed Rape 'boheme') · B. napus 'Brora' (Rutabaga) · B. napus 'Cash' (Oil Seed Rape 'cash') · B. napus 'Central' (Oil Seed Rape 'central') · B. napus 'Color' (Oil Seed Rape 'color') · B. napus 'Crosser' (Oil Seed Rape 'crosser') · B. napus 'Cr 34' (Oil Seed Rape 'cr 34') · B. napus 'Cr 42' (Oil Seed Rape 'cr 42') · B. napus 'Cr 45' (Oil Seed Rape 'cr 45') · B. napus 'Cr 49' (Oil Seed Rape 'cr 49') · B. napus 'Cr 51' (Oil Seed Rape 'cr 51') · B. napus 'Cs 39' (Oil Seed Rape 'cs 39') · B. napus 'Cult' (Oil Seed Rape 'cult') · B. napus 'C 604251' (Oil Seed Rape 'c 604251') · B. napus 'C 604251 Ms' (Oil Seed Rape 'c 604251 Ms') · B. napus 'C 999031 Ms' (Oilseed Rape 'c 999031 Ms') · B. napus 'Digital' (Oilseed Rape 'digital') · B. napus 'Dot' (Oil Seed Rape 'dot') · B. napus 'Dr 30' (Oil Seed Rape 'dr 30') · B. napus 'Dwarf Essex' (Canadian Turnip) · B. napus 'Eiffel' (Oil Seed Rape 'eiffel') · B. napus 'Elysee' (Oil Seed Rape 'elysee')

More Info

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Further Reading

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Notes

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Contributors

Identifiers

Footnotes

  1. "Brassica". in Flora of China Vol. 8 Page 16. Published by Science Press (Beijing) and Missouri Botanical Garden Press. Online at EFloras.org. [back]
Last Revised: 2014-05-09