Adromischus hallii (engl) PDF Imprimer E-mail
Adromischus - species
Écrit par P.C. Hutchison   
Dimanche, 14 Décembre 2008 17:47

ICONES PLANTARUM SUCCULENTARUM

1. Adromischus hallii P. C. Hutchison*.

*University of California Botanical Garden Contribution Number 137.

By P. C. HUTCHISON

Cactus and Succulent Journal US XXVIII  Nr. 5 1956


[Now, this plant is Adromischus marianiae ‘Hallii’]

FIG. 111. Adromischus hallii P.C. Hutchison, the clonotype, U.C.B.G. n° 53.1115-2.


In 1953 the University of California Botanical Garden (Berkeley) received its first shipment of Crassulaceous plants from Mr. Harry Hall of the National Botanic Garden, Kirstenbosch, South Africa. In this shipment and in succeeding ones were several new taxa in Adromischus and of these the species described below was Mr. Hall's favorite. At the time it was forwarded to us in December, 1953, Mr. Hall wrote of it: "Another very interesting [Adromischus] was number 75/53 which I collected a few hundred yards from the sea near Alexander Bay where the rainfall is practically nil though sea fogs are prevalent. It is somewhat mealy leaved and very dwarf. I now recall that this species is among the herbarium sheets for it was in flower and I felt that it might well be unknown from that spot which is behind the wire fence which protects the precious diamondiferous gravel. We got special permission to cross to the striking and singular mountains on the coast there. The plants grew around the base of the hill where the loose, fine Namib sand formed the plains and where a few loose rocks gave them a modicum of anchorage . It was among some I sent Herre [H. Herre, Stellenbosch Botanic Garden, South Africa] for you but he may well be getting them established too. I do not want it to lose its powdery appearance though, as it assuredly will under too much glasshouse treatment." Later Hall added that the locality was called "Buchu Twins, about ten miles south of Alexander Bay." At the National Botanic Garden, Kirstenbosch, this species was grown as number 75/53, but it has since died there. Under cultivation here, under glass, it has retained its white coloring.

FIG. 112. Adromischus hallii P. C. Hutchison. 1. Leaf, side view, la. Leaf, apical view. 2. Leaf, top view and cross-sections. 3. Flower. 4. Perianth limb, expanded. 5. Perianth limb, recurved. 6. Bud. 7. Cross-section perianth tube at midpoint. 8. Stamen insertion. 9. Carpels. 10. Nectary scale. 11. Anther. 12. Anther apex. 1-2 natural size. 3-9, x 3. 10-11, x 9. Dots on 4, 5 and 8 indicate papillae: on 11-12, red spots. Drawing by Mrs. M. Blos.

Adromischus hallii P. C. Hutchison, sp. nov.

Planta nana; caules 1-2 cm. longi; folia arcte rosulata sessilia asymmetrice rotunda usque ad 2.5 (3.5) cm. longa lataque et usque ad 13 mm, crassa alba, margine apicali bullato incrassato concolori vel obscure fusco-rubro, omnibus sectionibus transversalibus saepe asymmetricis; flores 10-15 erecti solitarii; pedicelli usque ad 10 mm. longi; perianthii tubus glauco-viridis 14 mm. longus, superficie interiore laete viridi quadrante superiore papillosa, lobi patentes vel recurvati 2 mm. lati 3 mm. longi albidi et roseo-tincti marginibus fusco-rubri basi papillosi.

FIG. 113. Adromischus hallii Hutchis., U.C.B.G. No. 53.1115-1.


Roots tuberous. Stem erect, 1 to 2 cm. long, up to 1 cm. diam., gray, wrinkled. Leaves sub-opposite, forming a tight rosette, horizontal to erect, sessile, mostly asymmetrically rotund, usually as long as broad, up to 2.5 (3.5) cm. broad and long, up to 13 mm. thick, convex on lower face, concave or convex on upper face and also irregularly and shallowly channeled, gray-white, unspotted, the apical margin thickened, bullate, sometimes crisped on young leaves, concolorous to glaucous maroon, the cross-sections at any point of mature leaves usually asymmetrical. Inflorescence simple; peduncle ca. 20 cm. long, up to 4 mm. diam., gray-white, lower 7 to 9 cm. with 4 to 9 thick, blunt, ovate-deltoid to deltoid sterile bracts 1.5 mm, broad, up to 4 mm. long and up to 1.5 mm. thick; rachis 10 to 12 cm. long; flowers 10 to 15, erect, single. Pedicels gray-white, up to 10 mm. long, 2 mm. diam. at base and middle, 3.5 mm. diam. at apex. Calyx lobes deltoid, acute, sometimes purplish tipped, ca. 2 mm. wide and long. Perianth tube glaucous-green outside, bright green inside, 14 mm. long, 4 mm. diam. at base, narrowed to 3 mm. at middle and above, the cross-section at mid-point strongly pentagonal with rounded corners and indented at the sinuses, the sinuses extending as conspicuous indentations of the tube to ca. 7 mm. from the apex, inconspicuous below there, the tube throat conspicuously and densely papillose, the papillae yellow, translucent; limb lobes spreading or recurved, oblong-ovate, somewhat acute, 2 mm. broad, 3 mm. long, pale whitish, tinged faintly with lavender or rose, with dark purplish maroon margins, bases papillose, the lower papillae yellow, the upper colorless. Stamen filaments didymous at about the middle of the tube, 3 to 4 mm. long, green or yellow-green; anthers included, oblong, creamy yellow with many red spots in longitudinally arranged masses along the grooves and also at the apex below the terminal translucent globule. Carpels ca. 11 mm. long, green, the styles subulate, pale yellowish green, the stigmas unenlarged, included, Nectary scales 1 mm. long, 1.5 mm. broad, the apex shallowly concave, the sides convex, with rounded corners, white or greenish white.

FIG. 114. Adromischus hallii Hutchis., U.C.B.G. No. 53.1115-3.

South Africa: Namaqualand, at the base of the Buchu Twins ca. 10 miles south of Alexander Bay, originally collected by H. Hall, University of California Botanical Garden number 53.1115-2 (BOL-Holotype).

Three plants of this new species were received from Mr. Hall and survive in cultivation here. Clone -2 was chosen as the clonotype and from it the drawing and the holotype were prepared. There is no significant vegetative variation between the three clones.

Adromischus hallii belongs with a group of Namaqualand species that includes A. herrei (Barker) Poellnitz, A. marianae (Marloth) Berger, A. kubusensis Uitewaal, A. antidorcatus Poellnitz and A. rodinii Hutchison. It differs from all these species by its sessile asymmetricaI white leaves. This group of species appears to be sufficiently natural to be considered a section. However there are some additional taxa to be described which belong here and until they are studied further the sectional diagnosis will be delayed.

The specific name honors the collector, Mr. Harry Hall of the National Botanic Garden, Kirstenbosch, Newlands, C. P., Union of South Africa, whose many collections of African succulents, particularly from the Cape and from Namaqualand, are especially noteworthy for the number of rare and new species and his fine habitat notes. Mr. Hall responded to my request for a brief biographical statement with the following: "I underwent the usual horticultural training: Reading, John Innes Horticultural Institute, Kew, and a year at La Mortola. I have been interested in succulents since 1932 and from 1933 to 1947 was in charge of the Darrah collection of cacti and succulents in Manchester, England, apart from the war years when I was in the R. A. F. Since coming here Kirstenbosch in 1947 I have devoted all my spare time, apart from various "official" expeditions, to plant collecting, largely succulents."

Mr. Hall has published a number of descriptive accounts of his travels in South Africa in the British cactus journals and recently he wrote an excellent small handbook on some African succulents ("Common Succulents" by H. Hall, Longmans, Green & Co., Cape Town, 1953, xv + 32 pp., 4 color plates showing 16 species). Several years ago a Euphorbia which he collected was named in his honor (Eurphorbia hallii R. A. Dyer, Journ. So. Afr. Bot. 19 (4): 135-136, pl. 19, 1953).


Fig. 115. Adromischus hallii Hutchis., the clonotype, U.C.B.G. No. 53.1115-2 inflorescence. x 0.7

 

 

 

 

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