Aloe cremnophila and A. jacksonii are described and illustrated as obligate cremnophytes, namely plants that only grow on cliffs. A. cremnophila is endemic to Somalia, whilst A. jacksonii comes from the Ogaden in Ethiopia

Walker, Colin

English

Open Research Online (Open)

Open Research OnlineThe Open University’s repository of research publicationsand other research outputsAloe cremnophila and Aloe jacksonii - cliff-dwellersfrom the Horn of Africa.Journal ItemHow to cite:Walker, Colin (2014). Aloe cremnophila and Aloe jacksonii - cliff-dwellers from the Horn of Africa. NorthantsNews, 25(2) pp. 14–16.For guidance on citations see FAQs.c© 2014 The AuthorVersion: Version of RecordLink(s) to article on publisher’s website:http://northants.bcss.org.uk/nl252/nl252aloe.htmCopyright and Moral Rights for the articles on this site are retained by the individual authors and/or other copyrightowners. For more information on Open Research Online’s data policy on reuse of materials please consult the policiespage.oro.open.ac.uk14 My plant of Aloe cremnophila is flowering for me for the first time, and such an exciting event makes it worthy of a report for Northants News.  The plant was obtained as a single stem back in 2009 from Brian McDonough of the Glasgow branch. As you can see from the photo it has grown well, and in the 4½ years in my care has produced a clump of 20 branches that is currently accommodated in a 25 cm diameter pot that I grow as a hanging pot. The branches could be described as being procumbent rather than pendulous, although the oldest and longest stem does hang down. Its leaves are up to 13 cm long, are uniformly grey-green in colour without spots, but with small sharp teeth up to 2 mm long on the leaf margins. So I would describe my plant as being reasonably large, and is now flowering for the first time, but it has only produced a single spike. This is erect, unbranched, just over 30 cm tall, with flowers about 26 mm long, pink but yellow-green at the mouth. Reynolds (1961) said that “Of several plants cultivated in my garden at Bryanston, Johan-nesburg, only one stem pro-duced an inflorescence”. Simi-larly my plant has been a re-luctant flowerer, and Brian’s has yet to flower. From this I think it’s safe to conclude that this species is a rather shy flowerer indeed.                  Aloe cremnophila and Aloe jacksonii                                  – cliff-dwellers from the Horn of Africa    Colin C. Walker Above: Aloe cremnophila in a 25 cm diameter pot. Below: Aloe jacksonii in an 8 cm square pot.    15 My plant is a propagation of ISI 1450, which in turn was propagated from the type collection Reynolds 8450B which was used to describe the species. The plant was first collected by Peter Bally in October 1956 on cliff faces of Daloh Es-carpment at 6,500 feet (1,970 m), about 13 miles N. of Erigavo, Somalia, and it is currently known from no other location, so the species could be described as a narrow endemic with a very restricted distribution. The closest relative to this species ap-pears to be A. jacksonii from the Ogaden in Ethiopia, which has similar short, erect or procumbent stems which branch from the base to form clumps, whilst the leaves are similar in shape with a rough surface, but are spotted. A. jacksonii was named for Major Jackson, who discov-ered it at El Kerre in Ethiopia in 1943 whilst stationed there during the Second World War. Major Jackson wrote that “El Kerre is a strange rock outcrop with pre-cipitous sides, and the station was built below the precipice. There is a steep path winding up a cleft, and the aloes were found along the edge at the top” (Reynolds, 1955). However, M. Dioli revisited El Kerre in 2000, searched for A. jacksonii but was unable to locate it, but instead found another species which he later described as A. elkerriana (Carter et al., 2011). There are, therefore, mysteries surrounding these plants. Firstly, it is strange that Jackson didn’t find A. elkerri-ana back in 1943, because it is appar-ently quite common at El Kerre. Sec-ondly, the origin of A. jacksonii is now uncertain: did it ever grow at El Kerre, has it died out from that location, or did Jackson incorrectly report its type local-ity? Whichever of these possibilities turns out to be correct, currently this species is only known from cultivated material from the original collection. A. cremnophila was so named because it only grows on cliffs, i.e. it is cliff-loving or a cremnophyte, a plant that grows on cliffs. However it is not unique as an Aloe that only grows on cliffs, i.e. is an obligate cremnophyte. A. jacksonii and A. elkerri-ana have already been discussed. Other species include: A. inamara, A. mendesii (Angola); A. ankoberensis, A. downsiana, A. pulcherrima (Ethiopia); A. amicorum, A. doddsiorum, A. tartarensis (Kenya); A. corallina, A. huntleyana, A. omavandae, Above: Flower spike of Aloe cremnophila, c. 30 cm tall.. 16 A. pavelkae (Namibia); A. collenetteae (Oman); A. squarrosa (Socotra); A. hardyi, A. meyeri (South Africa); A. toro-roana (Uganda) and A. pendens, A. yem-enica (Yemen) (Carter et al., 2011). Fur-ther afield and in other groups of succu-lents, cliff-dwellers are also known. In Mexican Crassulaceae, for example, the two species of the genus Cremnophila were separated from Echeveria and Se-dum partly because of their cliff-dwelling habit, and most species of the more fa-miliar genus Pachyphytum also grow hanging down from precipitous cliffs. In southern Africa a wide range of species has been discovered on cliffs. These plants were the subject of Ernst van Jaarsveld’s PhD. thesis and rumour has it that these will become the basis of a forthcoming book from this prodigious author, so we eagerly await further reve-lations on cliff-dwelling succulents in, hopefully, the not too distant future. References Carter, S., Lavranos, J.J., Newton, L.E. & Walker, C.C. (2011). Aloes - The defini-tive guide. Kew Publishing, Royal Botanic Gardens, Kew / British Cactus & Succu-lent Society.  Reynolds, G.W. (1955) A new Aloe from Ethiopia. J. So. Afr. Bot., 21: 59-61, pl. X. Reynolds, G.W. (1961) A new Aloe from Somali Republic. J. So. Afr. Bot., 27: 77-79, pls. XIII & XIV.                                                      Colin (colin.walker@open.ac.uk) 

<i>Aloe cremnophila</i> and <i>Aloe jacksonii</i> - cliff-dwellers from the Horn of Africa.

http://oro.open.ac.uk/42344/1/__userdata_documents4_ctb44_Desktop_Newletter252aloes.pdf

<i>Aloe cremnophila</i> and <i>Aloe jacksonii</i> - cliff-dwellers from the Horn of Africa.

Abstract

Similar works

Full text

Available Versions

Open Research Online (Open)