Eucalyptus lehmannii · bushy yate
Eucalyptus conferruminata · bald island marlock
When the need arises for a screen tree that bears foliage down to ground level, is not much more than 10 feet tall, spreads as a screen to more than 10 to 20 feet across, tolerates low rainfall, does not mind wind loaded with salt spray, can grow on salty mudflats, and ignores the calcareous accumulation of ages of small shellfish, one turns to the bushy yate. Thousands have been planted to hold back the wind and spray and to hide the desolate wetlands as we drive to San Francisco Airport on Bayshore Freeway. Hundreds have been planted along the Shoreline Trail in Mountain View as it curves around Shoreline Golf Links. There are thousands more through Berkeley and beyond and on Highway 101 around Santa Barbara. Punctuated at intervals by taller river red gums that catch the eye, the low unclipped hedge of bushy yates passes virtually unnoticed.
Close inspection will show that there are two forms of the bushy yate in the Bay Area, a situation that I reported in California Report on Eucalyptus, Australian Plants, vol. 6, page 214, 1971. The drawing by Reg Campbell (the artist who painted the portrait of Russel V. Lee at the Palo Medical Foundation) of a specimen collected on campus has opercula large enough for kids to fit on their fingertips like thimbles and play “witches’ fingers.” These caps have three or four distinct edges, rather like those on a banana. Of seven bud and fruit samples in my possession, four have 15 buds, the others have 13, 14, and 16. These features agree with illustrations published by several authors.
In 1980 D.J. and S.G.M. Carr found that the thousands of windbreak trees planted in Australia as E. lehmannii did not agree with the holotype. They proposed replacing E. lehmannii by the existing name E. conferruminata (which means “welded together”). They reported that on the southwest Australian coast the latter always occurs as a tree. Photographs of E. conferruminata show buds with long narrow horns in large numbers (19 to 35). In the Bay Area, for example along Shoreline Boulevard, Mountain View, there are many bushy yates, often of treelike stature, with such buds. On campus both forms can be seen together on Serra Street a few yards north of the Recycling Center driveway. E. lehmannii opercula are narrower (4–7 mm wide) than those of E. lehmannii (8–13 mm wide). Sunset’s Western Garden Guide reports that trees currently sold in American nurseries as E. lehmannii are likely E. conferruminata.
Oregon Expressway was lined on one side by bushy yates until the road was widened. Three substantial multi-trunked 30-foot high specimens remain on the north side of 2411 High Street, Palo Alto, a dead-end section of High Street that only can be reached from Colorado Avenue. The fallen opercula are long, narrow, smooth, curved horns that are red on the sunlit side but otherwise yellow. The branches droop close to ground level, as appropriate for a windbreak. If you examine a few untended trees it will strike you that the habit of having foliage to ground level results from natural splitting of lower branches to form props; the effect of this in the wild is to steady the whole plant against windthrow.
Tree people will have noticed that each eucalypt tends to have 1, 3, 7, or 15 buds, following the formula 2ÏF;-1, where n may vary from 1 to 5. Bushy yate often has 15 and in other cases tries to reach 31 but at the higher numbers some buds may fail to develop. The fruits fuse together to form irresistible collectibles that can be as big as a fist and are suitable for dry arrangements.
Sunset magazine ran an article advocating the bushy yate as an accent tree for small gardens and showed a specimen pruned to a small erect form. It is not clear which of the two forms this article referred to. Three campus specimens with the large opercula in public locations have been lost to development and should be replaced. Meanwhile, three standard trees, one with the large straight opercula and two with the thin curved opercula, have been planted on Serra Street along the east fence of the Recycling Center.
Related material: Eucalyptus checklist.
About this Entry: The main text of this entry is from the book Trees of Stanford and Environs, by Ronald Bracewell, published 2005. John Rawlings subsequently added Shoreline Golf Links note, note on Serra St location having both forms, and Sunset’s note on the confusion.